Tag Archives: nutrition

Shifting to a healthier diet can increase your lifespan by up to a decade

New research is showcasing how a more healthy, balanced diet — including more legumes, whole grains, and nuts, while cutting down on red and processed meat — can lead to longer lives.

Image via Pixabay.

“You are what you eat” is an age-old saying, but a new study from the University of Bergen says that we also live as long as what we eat. The healthier and more diverse our diets, the healthier and longer our life expectancy (LE) becomes, it reports.

The paper estimates the effect of such changes in the typical Western diets for the two sexes at various ages; the earlier these guidelines are incorporated into our eating habits, the larger the improvements in LE, but older people stand to benefit from significant (if smaller) gains as well.

Change your meals, enjoy more meals

“Our modeling methodology used data from [the] most comprehensive meta-analyses, data from the Global Burden of Disease study, life-table methodology, and added analyses on [the] delay of effects and combination of effects including potential effect overlap”, says Lars Fadnes, a Professor at the Department of Global Public Health at the University of Bergen who led the research, in an email for ZME Science.

“The methodology provides population estimates under given assumptions and is not meant as individualized forecasting, with uncertainty that includes time to achieve full effects, the effect of eggs, white meat, and oils, individual variation in protective and risk factors, uncertainties for future development of medical treatments; and
changes in lifestyle.”

Dietary habits are estimated to contribute to 11 million deaths annually worldwide, and to 255 million disability-adjusted life-years (DALYs). One DALY, according to the World Health Organization “represents the loss of the equivalent of one year of full health”. In other words, there’s a lot of room for good in changing what we eat.

The team drew on existing databases to develop a computerized model to estimate how a range of dietary changes would impact life expectancy. The model is publicly available as the online Food4HealthyLife calculator, which you can use to get a better idea of how changing what you eat can benefit your lifespan. The team envisions that their calculator would also help physicians and policy-makers to understand the impact of dietary choices on their patients and the public.

For your typical young adult (20 years old) in the United States, the team reports that changing from the typical diet to an optimal one (as described by their model) could provide an increase in LE of roughly 10.7 years for women and 13 years for men. There is quite some uncertainty in these results — meaning that increases for women range between 5.9 years and 14.1, and for men between 6.9 and 17.3 — due to the effect of factors that the model doesn’t factor in, such as preexisting health conditions, socioeconomic class, and so on. Changing diets at age 60 would still yield an increase in LE of 8 years for women and 8.8 years for men.

“The differences in life expectancy estimates between men and women are mainly due to differences in background mortality (and particularly cardiovascular disease such as coronary heart disease, where men generally are at higher risk at an earlier age compared to women),” prof. Fadnes explained for ZME Science.

The largest gains in LE would be made by eating more legumes, more whole grains, more nuts, less red meat, and less processed meat.

So far, the research focused on the impact of diet on LE, but such changes could be beneficial in other ways, as well. Many of the suggestions the team makes are also more environmentally sustainable and less costly, financially. The team is now hard at work incorporating these factors into their online calculator, in order to help people get a better understanding of just how changes in diet can improve their lives, on all levels involved.

“We are working to include sustainability aspects in Food4HealthyLife too. Based on former studies, the optimal diets are likely to have substantial benefits compared to a typical Western diet also in terms of reduction in greenhouse gas emissions, land use, and other sustainability facets,” he added for ZME Science. We have not systematically investigated financial aspects yet, but several of the healthy options could also be cheap, such as legumes and whole grains.”

The paper “Estimating the Impact of Food Choices on Life Expectancy: A Modeling Study” has been published in the journal PLoS Medicine.

Healthier, more nutritious diets have a lower environmental impact — at least in the UK

More nutritious and healthy diet options can also help the climate, says a new analysis from the University of Leeds.

Image via Pixabay.

Our combined dietary habits can be a significant source of greenhouse gas emissions. Worldwide, food production accounts for roughly one-third of all emissions. This isn’t very surprising, since everybody needs to eat; but there are little tweaks we can apply to our lives which, added up, can lead to significant benefits for the climate.

New research at the University of Leeds reports that more nutritious, less processed, and less energy-dense diets can be much more sustainable from an environmental point of view than more common alternatives. While “less energy-dense” might sound like a bad thing, calorie content doesn’t translate into nutrient content. In other words, many energy-rich foods may actually just leave us fatter and malnourished.

Clean dining

“We all want to do our bit to help save the planet. Working out how to modify our diets is one way we can do that,” the authors explain. “There are broad-brush concepts like reducing our meat intake, particularly red meat, but our work also shows that big gains can be made from small changes, like cutting out sweets, or potentially just by switching brands.”

Similar analyses of the impacts of dietary options on the environment have been performed in the past. While their findings align well with the conclusions of the study we’re discussing today, they focused on broad categories of food instead of specific items. The team wanted to improve the accuracy of our data on this topic.

For the study, they pooled together published research on greenhouse gas emissions associated with food production to estimate the environmental impact of 3,233 specific food items. These items were selected from the UK Composition Of Foods Integrated Dataset (COFID). This dataset contains nutritional data regarding every item on the list and is commonly used to gauge the nutritional qualities of individuals’ diets.

The team used this data to evaluate the diets of 212 participants, who were asked to report what foods they ate during three 24-hour periods. In the end, this provided a snapshot of each participant’s usual nutritional intake and the greenhouse emissions generated during the production phase of all the items they consumed.

What the results show, in broad strokes, is the environmental burden of different types of diets, broken down by their constituent elements.

According to the findings, non-vegetarian diets had an overall 59% higher level of greenhouse gas emissions compared to vegetarian diets. This finding isn’t particularly surprising; industrial livestock farming is a big consumer of resources such as food and water and produces quite a sizeable amount of emissions from the animals themselves, the production of fodder, and through the processing and storage of meat and other goods.

Overall men’s diets tended to be associated with higher emissions — 41% more on average than women’s diets — mainly due to higher meat consumption.

People who exceeded the recommended sodium (salt), saturated fat, and carbohydrate intake as set out by World Health Organization guidelines generated more emissions through their diets than those who did not.

Based on these findings, the authors offer their support for policies aimed at encouraging sustainable diets, especially those that are heavily plant-based. One other measure they are in support of is policy that promotes the replacement of coffee, tea, and alcohol with more sustainable alternatives.

The current study offers a much higher-resolution view of the environmental impact of different food items, but it is not as in-depth as it could be. In the future, the authors hope to be able to expand their research to include elements such as brand or country of origin to help customers better understand what choices they’re making. They also plan to include broader measures of environmental impact in their analyses, not just greenhouse gas emissions.

For now, the findings are based only on data from the UK, so they may not translate perfectly to other areas of the globe.

The paper “Variations in greenhouse gas emissions of individual diets: Associations between the greenhouse gas emissions and nutrient intake in the United Kingdom” has been published in the journal PLOS One.

What counts as fruits and veggies for the “five a day”? This study clears things out

“What should we eat?” is a question you’ll hear a lot from your significant other. While they may not be sure, a new paper is: about 2 servings of fruit and 3 servings of vegetables every day.

New research from the Harvard T. H. Chan School of Public Health, Boston, reports that getting five servings of fruits and vegetables every day (particularly getting 2 of fruit and 3 of vegetables) is the optimal amount for all your health needs. This ratio was found to help reduce the risks of developing numerous chronic health conditions, including cardiovascular disease and cancer.

However, only 1 in 10 adults in the U.S. eat enough fruits and vegs, the study adds, citing statistics from the U.S. Centers for Disease Control and Prevention.

Pear-shaped snacks

“While groups like the American Heart Association recommend four to five servings each of fruits and vegetables daily, consumers likely get inconsistent messages about what defines optimal daily intake of fruits and vegetables such as the recommended amount, and which foods to include and avoid,” said lead study author Dong D. Wang, M.D., Sc.D., an epidemiologist, nutritionist and a member of the medical faculty at Harvard Medical School and Brigham and Women’s Hospital in Boston.

The paper looked at two studies — the Nurses’ Health Study and the Health Professionals Follow-Up Study — which together followed nearly 100,000 adults worldwide for up to 30 years. Both studies included detailed dietary information on its participants, which were collected every two to four years. The team also included data on fruit and vegetable intake alongside mortality rates from a further 26 studies that included about 1.9 million participants in 29 countries and territories in North and South America, Europe, Asia, Africa, and Australia.

All in all, the analysis revealed that:

  • About 5 servings of fruits and vegetables daily was associated with the lowest risk of death among participants. Having more than five servings didn’t seem to confer any additional benefits.
  • Having 2 servings of fruit and 3 of veggies daily seemed to yield the best results; these participants had a 13% lower risk of death from all causes, a 12% lower risk of death from cardiovascular disease, a 10% lower risk of death from cancer, and a 35% lower risk of death from respiratory disease, compared to participants who ate 2 servings of fruit or vegetables per day.
  • Starchy foods (corn, potato, peas, fruit juices, so on) were not associated with this reduction in mortality. In other words, they don’t count towards your 5 daily servings.
  • Leafy greens such as spinach, lettuce, or kale, alongside fruits and vegetables rich in beta carotenes and vitamin C (brightly-colored items such as carrots, bell peppers, berries, or citrus fruits) do count towards these 5 servings.

“Our analysis in the two cohorts of U.S. men and women yielded results similar to those from 26 cohorts around the world, which supports the biological plausibility of our findings and suggests these findings can be applied to broader populations,” Wang said.

The team hopes that their work will help make it a bit clearer to everybody on exactly what constitutes good dietary habits, and which items count towards the succinct public message of 5-a-day. This amount, says Wang, likely “offers the most benefit in terms of prevention of major chronic disease” and is relatively achievable on a day-to-day basis.

One particularly important finding here is that not all fruits and vegetables offer the same benefits — some even offer none. Of particular note here are starchy vegetables, fruit juices, and potatoes, which offer no benefits despite the fact that current dietary guidelines treat these items the same as other fruits or vegetables. Fruit juices contain a lot of sugar, for instance, while potatoes aren’t as good for you as other vegetables.

Still, the study so far is only observational, which means that it found an association between certain dietary factors and a lower risk of death. But as you all surely know by now, correlation does not imply causations — just because these two elements are associated doesn’t mean that one causes the other. More work is needed to establish a solid cause-and-effect relationship, but in the meantime, it can’t hurt to chow down on some fruits and vegs.

The paper “Fruit and Vegetable Intake and Mortality: Results From 2 Prospective Cohort Studies of US Men and Women and a Meta-Analysis of 26 Cohort Studies” has been published in the journal Circulation.

The food industry is skewing research, but we’re onto them now

The food industry could be actively working against public health by influencing the results of studies in their favor.

Image credits Stefan Divily.

New research reports that around 13.4% of the nutrition studies it analyzed disclosed ties to the food industry. Studies in which the industry was involved were more likely to produce results that were favorable to its interest, the team adds, raising questions in regards to the merits of these findings.


“This study found that the food industry is commonly involved in published research from leading nutrition journals. Where the food industry is involved, research findings are nearly six times more likely to be favourable to their interests than when there is no food industry involvement,” the authors note.

It’s not uncommon for industry to become involved with research — after all, they have a direct stake in furthering knowledge in their field of activity. This can range from offering funding to assigning employees to research teams for support or active research.

The current paper comes to show that, at least in the food industry, such activities are actively skewing and biasing research into nutrition. It is possible, the team reports, that this can put public health at risk as corporate interests can start dictating what findings see the light of day, where, and in what form. Such findings are worrying since corporations are notorious for putting profits above anything else, including truth or the common good.

In order to get a better idea of just how extensive the influence of industry is in food-related research, the team — led by Gary Sacks of Deakin University in Melbourne, Australia — analyzed all papers published in the top 10 peer-reviewed academic journals related to diet or nutrition. They looked at which had ties to the industry such as funding from food companies or affiliated organizations, and then whether or not the authors went out of their way to support industry interests.

Roughly 13.4% of the articles had some level of industry involvement, with some journals bearing more of the blame than others. The authors explain that studies with industry involvement were over five times more likely to favor industry interests compared to a random sample of studies without involvement (55.6% vs 9.7% for the latter).

Such figures offer a pretty big warning sign that industry involvement could promote research bias or help push an agenda at the expense of quality science (such as the neglect of topics that are important for public health but go against industrial interests). The authors suggest several mechanisms that could be employed to preserve the quality of nutrition research.

The paper “The characteristics and extent of food industry involvement in peer-reviewed research articles from 10 leading nutrition-related journals in 2018” has been published in the journal PLOS One.

Green Mediterranean diet may be even better for losing weight than regular Mediterranean

In recent years, the Mediterranean diet has emerged as one of the healthier eating patterns out there. Now, a new study suggests that the ‘green’ Med diet (which features even more plant-based foods) may be even better for health than the traditional Mediterranean diet.

Some of the core foods of the Mediterranean diet. Image credits: G. Steph / Wikipedia.

It’s not exactly a diet in the strict sense — it’s rather a set of eating habits inspired by Mediterranean countries like Spain, Italy, or Greece. The diet can’t be strict because there’s no one single ‘Mediterranean’ way of eating — it varies from country to country and even from area to area. Some even argue that it’s not only about what you eat, but also about how you eat.

The general idea, however, is that you’re supposed to eat a lot of plant foods: fruits, vegetables, legumes, nuts, beans, whole cereals and grains. When or if you do eat meat, it’s fish and maybe chicken — red meat doesn’t have a central spot in the Mediterranean diet.

Although scientists are still debating just how good the Mediterranean diet is, most studies seem to suggest that it’s quite healthy. A 2017 review of studies found evidence that practicing a Mediterranean diet could lead to a decreased risk of cardiovascular diseases, overall cancer incidence, neurodegenerative diseases, diabetes, and early death. Another 2018 review echoed the findings, reporting that the Mediterranean diet may improve overall health status.

Now, a new study reports that, when it comes to weight loss at least, the ‘green sister’ of the Mediterranean may hold even more benefits.

Fiber, healthy fats, and polyphenols, are thought to be the key to the benefits of the Mediterranean diet. In a new study, researchers wanted to see whether an even higher intake of these compounds (and an even lower red meat intake) is even better. They randomly assigned 294 sedentary and moderately obese people into three dietary groups:

  • the first group only received a guide on how to achieve a healthy diet and boost their physical activity;
  • the second group received the same guide, plus advice on following a calorie-restricted Mediterranean diet (1500-1800 kcal/day for men and 1200-1400 kcal/ day for women);
  • the third group received the same thing as the second group, but featuring a green version of the Mediterranean diet (the so-called green Med).

Specifically, the green Med diet included 28 g/day walnuts, 3-4 cups/day of green tea, an avoidance of red meat, and 100 g frozen cubes of Wolffia globosa (cultivated Mankai strain), a high protein form of the aquatic plant duckweed, to substitute animal protein.

After six months, the researchers checked up on the participants. All three groups lost weight, but the results were striking: the healthy diet participants (first group) lost 1.5 kg. The Mediterranean diet participants lost 5.4 kg. Lastly, the green Med participants lost 6.2 kg. Waist circumference also shrank by 4.3 cm, 6.8 cm, and 8.6 cm respectively. Similar drops were also observed for cholesterol.

It’s still a small-scale study, but the results warrant further investigation, researchers say.

“Education and encouragement to follow a green Med dietary pattern in conjunction with physical activity has the potential to be a major contributor to public health as it may improve balancing of cardiovascular risk factors, eventually preventing cardiovascular morbidity and mortality,” the authors note in the study.

The dietary results of the Mediterranean diet have not always been clear, as is often the case in nutritional studies. However, this could be at least in part owed to the many varieties of the Mediterranean diet. If many of the benefits come from a subset of Mediterranean foods, it could be worth exploring particular variants of the Mediterranean diet.

Ultimately though, both types of Mediterranean diet seem to offer significant advantages when it comes to weight loss. Reducing your calorie intake is obviously one of the first things that gets recommended for weight loss, but some diets make it easier than others — and are also healthier than others.

“Our findings suggest that additional restriction of meat intake with a parallel increase in plant-based, protein-rich foods, may further benefit the cardiometabolic state and reduce cardiovascular risk, beyond the known beneficial effects of the traditional Mediterranean diet,” the study concludes.

The study has been published in the British Medical Journal.

Debunking the soy-estrogen problem and other soy myths

Soy is a unique food that can have both estrogenic and anti-estrogenic effects on the body. Studies sometimes present unclear or conflicting evidence, but the evidence suggests that in healthy individuals, soy provides significant benefits, especially as an alternative to red meat.

Not soy fast

Soy has been consumed in Asian countries for thousands of years — there’s evidence that it has been consumed since 9,000 BC. In recent decades, soyfoods have also become increasingly popular in non-Asian countries, largely because they are versatile and rich in protein. Soy protein is better than many other sources of protein as it contains all the essential amino acids.

At the same time, soy is often shunned for fear that it interferes with hormones. While some small-scale studies have cast some doubt on soy’s beneficial properties, recent large-scale studies have helped us understand soy’s effects on the body much better.

There have been several large-scale studies on the health effects of soy. These results suggest that soy has either a beneficial or at worst, a neutral effect on various health conditions.

Soy is a nutrient-rich food that can be safely consumed multiple times a week and is likely to provide health benefits, especially when consumed as an alternative to red meat. While the extent of its benefit remains a matter of scientific debate, soy scaremongering has no scientific basis to stand on. Studies have shown that in moderate or even high quantities (an average of 1-2 servings per day), there is no relevant adverse effect in healthy individuals.

Tofu, one of the most popular soy products, can be an important part of a healthy diet with no significant drawbacks. Image credits: Anh Nguyen.

Is soy healthy?

The macronutrient composition of the soybean is different from other legumes, which is also why it’s so sought after. Soy is very rich in protein (comparable with meat in that regard but without the saturated fat and cholesterol). Soybean is also a good source of essential fatty acids and soy compounds that lower cholesterol levels. Studies have consistently found that reducing the animal protein and replacing it with plant protein from soy reduces cardiovascular risk, which is one of the main reasons for soy’s increasing popularity.

The soybean is also a good source of a variety of vitamins and minerals, such as potassium (which is notable because intake of this mineral is often suboptimal) and iron.

It’s hard to isolate the effects of soy from other parts of the diet, particularly as soy can be cooked and processed in multiple ways, and not all are similar.

“Soyfoods have long been recognized for their high-protein and low-saturated fat content, but over the past 20 years an impressive amount of soy-related research has evaluated the role of these foods in reducing chronic disease risk. Much of this research has been undertaken because the soybean is essentially a unique dietary source of isoflavones, a group of chemicals classified as phytoestrogens. The estrogen-like properties of isoflavones have also raised concern, however, that soyfoods might exert adverse effects in some individuals,” a recent study noted.

However, the concerns stem primarily from studies on animals, whereas human research supports the safety and benefits of soyfoods on healthy individuals.

Even in the most vulnerable categories, soy consumption seems safe. Approximately 20–25% of U.S. infants receive at least some soy-based formula (not soy milk) in their first year, and several studies documenting this have reported no negative health issues associated with this practice in babies or in adults who consumed soy-based formula as babies. Studies have found little to no differences between babies fed soy or cow’s-milk-based formula.

However, soy can be consumed in different forms, and some are not as healthy as others. Processed burgers generally tend to be far less healthy than things like tofu, for instance.

The bottom line on ‘is soy healthy’: Soy is an excellent source of nutrients, although processed forms may be far less healthy. The benefits of soy may depend on the form in which it is consumed.

Soy and female hormones

The effect of soy on women’s bodies has been often questioned. The reason is that soy contains phytoestrogens, plant hormones somewhat similar to estrogens. These are mainly two isoflavones (genistein and daidzein), and soy is far from the only plant to contain these hormones — studies have shown that a wide variety of fruits and nuts contain the same hormones. However, plant estrogens typically make a low percentage of the total ingested estrogens, especially in the Western world. Most of the estrogens we eat come from milk and dairy products; compared to that, soy only plays a minor part.

The controversy stems from the fact that the two isoflavones can act like estrogen (the female sex hormone) and estrogen plays a role in many biological processes from breast cancer to reproduction. However, these phytoestrogens have a much weaker effect than human estrogen — and while they share similarities to human hormones, they are structurally different. Furthermore, in some instances, phytoestrogens may even block the action of estrogen, which further complicates the issue.

Basically, while high levels of estrogen have been linked to an increased risk of breast cancer, soy foods don’t contain high enough levels of isoflavones to increase the risk of breast cancer.

“Soy has a relatively high concentration of certain hormones that are similar to human hormones and people got freaked out about that,” says Isaac Emery, a food sustainability consultant, for The Guardian. “But the reality is you would have to consume an impossibly large amount of soy milk and tofu for that to ever be a problem.”

Unfermented soy foodsIsoflavone content (mg)Protein (g)
soy milk, 1 cup67
tofu (bean curd), soft, 3 ounces208
soybeans, mature, boiled, ½ cup5515
soybeans, dry roasted, 1 oz.4011
edamame, boiled, ½ cup1611
soy cheese, 1oz.24
soy burger, 1 patty514
It’s worth noting that not all soy foods are alike. Source: Harvard University.
Fermented soy foodsIsoflavone content (mg)Protein (g)
miso, 3 oz.3710
natto, 3 oz.7014
tempeh, cooked, 3 oz.3013
soy sauce, 1 tbsp0.020

Several studies have looked for this but failed to establish a connection — and furthermore, some studies suggest that soy might actually reduce the incidence of some types of cancer (though that evidence is still unclear).

High soya intake among women in Asian countries has been linked to a 30% lower risk of developing breast cancer compared to US women, who eat much less soya. For example, the average intake of isoflavones in Japan is 30-50 mg per day, compared to 3mg in Europe and the US.

At any rate, the best existing science at the moment suggests no reason to associate soy consumption with cancer risk. According to the American Cancer Society (ACS), while our understanding of estrogen is still improving, soy does not seem to pose any cancer risk.

Across the ocean, similar studies have come to similar conclusions. A recent review of the European Food Safety Authority found that isoflavones do not adversely affect the breast, thyroid, or uterus of postmenopausal women. No effect was found on endometrial thickness or the histopathology of the uterus after 30 months of supplementation with 150 mg/day of soy isoflavones.

Soy has also been sometimes regarded as a risk to the endometrial tissue. However, studies suggest otherwise. A review of 25 clinical studies found that isoflavones do not adversely affect the endometrium. Furthermore, a recent meta-analysis of 10 observational studies found that soy intake was inversely associated with endometrial cancer risk. Regarding endometriosis, studies have found either a neutral or a positive effect associated with soy milk.

It’s sometimes claimed that while soy is a healthy option for most women, it can be dangerous for women right before or during menopause. However, this has been disproven. A study in which women ingested 900 mg of soy isoflavones per day found “no significant changes in mean values for estrogenic effects or other laboratory measurements” — and 900 mg is essentially impossible to get through diet, no matter how much soy you eat.

In fact, some studies have found that soy isoflavones can help with menopause. Asian women who consume soy regularly have much lower rates of menopausal symptoms such as hot flashes, although the studies are contradictory and it’s still unclear if soy is responsible for this protective effect. The average blood concentration of the isoflavone genistein in Asian women is about 12 times higher than that of US because of higher soy consumption, although the possible benefits of soy remain uncertain.

Another study on obese postmenopausal women found that replacing at least some of the consumed animal protein with soy offers clears advantages in terms of regulating insulin and cholesterol.

However, very large quantities of soy consumption (more than 15 servings/week) might disrupt ovarian function, one study found.

“Although the levels of phytoestrogens typically found in soy foods pose minimal risk in the adult female, the female reproductive system is dependent on hormones for proper function and phytoestrogens at very high levels can interfere with this process.”

The bottom line on soy and female hormones: studies have found no reason for concern unless soy is consumed in extremely large quantities. Soy is linked to positive outcomes for women, though the extent of these effects is still being researched.

Soy and male hormones

The idea that soy is not good for men, that it will alter their hormone levels or make them grow “man boobs” is owed to advertising more than real science. The alleged evidence for this comes from two isolated case reports of elder Japanese men whose caloric intake came almost exclusively from soy. Yes, if all you eat is soy, you’re bound to have health problems — but that can be said for everything, if you just eat one food, you’re bound to get in trouble. A thorough review found that “that isoflavones do not exert feminizing effects on men at intake levels equal to and even considerably higher than are typical for Asian males.”

Concerns that the consumption of phytoestrogens might exert adverse effects on men’s fertility (such as lowered testosterone levels and semen quality) have been addressed in several studies.

Soy burgers have become increasingly popular lately.

The controversy was fueled by one highly circulated 2008 study quoted by the Daily Mail which found that in men with a low sperm count, soy was associated with an even lower sperm count (though not leading to infertility). However, the study had important limitations: it’s limited to only 99 men, the majority of participants 72%) were overweight or obese, and other dietary and lifestyle parameters were not factored in (for instance, red meat or junk food are also suspected of reducing sperm count, as is a sedentary lifestyle).

The study was contradicted by more recent research that found no such association. As it so often happens, this small study was misinterpreted as “soy kills your sperm,” although evidence suggesting otherwise is much more robust. Asian populations have regularly consumed soy for generations without exhibiting any fertility disorders and primate studies also found no connection between soy and the quality, quantity, or motility of sperm.

In one University of Minnesota study from 2009, fifteen placebo-controlled treatment groups were compared with a baseline. In addition, 32 reports involving 36 treatment groups were assessed in simpler models to ascertain the results.

The researchers found no indication of a hormone alteration, regardless of the type of soy that was consumed.

“No significant effects of soy protein or isoflavone intake on testosterone, sex hormone-binding globulin, free testosterone, or free androgen index were detected regardless of the statistical model,” the researchers wrote. “The results of this meta-analysis suggest that neither soy foods nor isoflavone supplements alter measures of bioavailable testosterone concentrations in men.

In a 2010 review of the medical evidence, researchers wrote that “isoflavones do not exert feminizing effects on men,” while a study on babies who were fed soy milk found no “estrogen-like” hormonal effects in the soy drinkers.

Another interesting study on patients with prostate cancer assessed how much phytoestrogens would need to be ingested to alter testosterone and estrogen levels in men — it would be almost impossible to consume that much. No effects on estrogen levels have been noted in numerous clinical studies in which men were exposed to as much as 150 mg/day isoflavones (which is already a huge quantity). Even when a study analyzed a dose of 450 – 900 mg of phytoestrogens per day for 3 months, it found only a small detectable change in testosterone levels and no feminizing effects.

“The intervention data indicate that isoflavones do not exert feminizing effects on men at intake levels equal to and even considerably higher than are typical for Asian males,” the study concluded.

To put that into perspective, 450 mg of phytoestrogen is a huge amount. The average consumption of isoflavones in Asian society is 15-50 mg per day, while in Western countries only about 2 mg per day. You could have yourself a soy feast every day and you still wouldn’t reach it:

  • 1 cup of cooked soybeans = 94 mg
  • 6 ounces of tempeh = 74 mg
  • 2 cups of soy milk = 60 mg
  • 6 ounces of tofu = 40 mg
  • 2 soy hot dogs = 22 mg
  • 4 oz of soy cheese = 8 mg
  • total = 298

Overall, the impact of soy on male hormones is nonexistent or negligible and it is strongly overshadowed by the positive nutritional advantages of soy compared to equivalent foods.

“These data do not support concerns about effects on reproductive hormones and semen quality,” one review concluded.

If you’re worried about your hormone levels and feminization, you’d be better off reducing the amount of alcohol you consume. Alcohol has been repeatedly linked to hormone disorders, and ethanol is essentially a testicular toxin known to disrupt testosterone and reduce fertility.

The bottom line on soy and male hormones: The weight of evidence suggests no association between soy and feminization or hormonal issues. If your calories don’t come exclusively from soy, you should be alright.

Soy and cardiovascular disease

Image credits: Kien Cuong Bui.

Soy has been found to reduce the incidence of cardiovascular diseases, although it’s still debatable to what extent this effect is owed to the soy itself or to the fact that soy is often replacing more harmful foods like red meat.

The first major study to support this was a 1995 meta-analysis of 38 controlled clinical trials, which found that eating 50 grams of soy protein per day (over a pound of tofu) reduces cholesterol by 12.9%. Other studies have found a similar but weaker effect, and the problems stem from how soy is consumed — not all soy foods are alike, and some processed foods may be less healthy than others.

Overall, however, soy has been linked to a lower risk of heart disease compared to protein from animal sources. Even though soy protein may have little or even no direct effect on cholesterol or artery health, it is generally good for the heart and blood vessels if it replaces less healthful choices like red meat, especially as it comes with plenty of vitamins, minerals, and is low in saturated fats.

It’s also noteworthy that cardiovascular protection was observed in women more than men. But, for both men and women, the discussion is about how and how much soy helps cardiovascular health, not about problems associated with consumption.

The bottom line on soy and cardiovascular health: some studies have reported positive effects associated with soy consumption. While the extent of that is being actively researched, soy is a healthier alternative to red meat.

Soy and cancer

In animal and cell studies, high dosages of isoflavones tend to stimulate cancer growth. But in real humans, it’s a completely different thing, and most studies suggest a protective effect rather than the opposite.

For instance, the Shanghai Women’s Health Study (the largest and most detailed study of soy and breast cancer risk) followed 73,223 Chinese women for over 7 years. It found that women who ate the most soy had a 59% lower risk of premenopausal breast cancer compared to those who ate the lowest amount of soy. The Breast Cancer Family Registry, another prospective study following 6,235 women diagnosed with breast cancer in the US and Canada found higher survival rates in women who consumed more soya.

Another concern links soy and the risk of prostate cancer — however, here too, the studies suggest the opposite: regular soya intake is associated with an almost 30% reduction in the risk of developing prostate cancer (though again, this is difficult to attribute directly to soya, it could be linked to the lower intake of red meat or more general lifestyle). The strongest evidence here comes from a meta-analysis of 30 case-control and cohort studies from the US, Europe, Japan, and China, which found that phytoestrogen is significantly associated with a reduced risk of prostate cancer.

Curiously, it’s not clear how this happens. Soya intake doesn’t affect testosterone levels in men, so it could simply be that a diet containing more soya is often healthier overall (although isoflavones have been found to inhibit metastasis).

The bottom line on soy and cancer: soy is associated with a reduction in the risk of breast and prostate cancer.

Traditionally-served tofu in Japan.

The Conclusions

It’s always challenging to study the health impacts of a particular food or ingredient. There have been hundreds of studies on the health impacts of soy, some bigger and more thorough, some a bit more shallow, all with their own limitations. Studies often show correlation without causation, but the weight of evidence strongly indicates health benefits from eating soya — even if it just replaces unhealthier foods.

The phytoestrogens in soy play a complex role in the human body and the mechanism, but most studies find neutral or positive effects. However, in some niche situations, specialy attention must be paid to soy (for instance soy may interfere with thyroid hormone medication). Evidence indicates soyfoods can be safely consumed by all individuals except those who are allergic to soy protein, which is a rare allergy.

Aside from the phytoestrogens, soy contains plenty of vitamins, minerals, and nutrients. Soy can also be prepared in different types of foods — and some are healthier than others.

As is always the case, soy is best consumed in a balanced diet. Any food consumed in extremes will likely lead to negative health outcomes.

Despite an increasing need, school meals are getting less healthy in the US

With classes canceled in up to 40 states, schools in the United States are still fulfilling an important need amid the coronavirus lockdown. Many families visit schools every day to get food as they can no longer afford it.

Credit Flickr.

As on any other school day, all schools are providing meals to families that have to meet the federal nutrition standards. But, instead of working to ensure that the meals remain nutritious, the Trump administration is rolling back healthier standards, health organizations claim.

Back in January, the federal government proposed new rules to allow more pizza, meat, and potatoes in schools instead of fresh vegetables, fruits, and whole grains. This means replacing standards that have been put in place by Michelle Obama.

The new rules mean schoolchildren could consume an additional eight cups per week of hash browns, french fries, or other potatoes instead of fruit in breakfast and other vegetables in lunch. Trump’s initiative has already been rejected by nearly 60 health organizations.

“These rollbacks fail to put children’s health first, which is the clear goal of school nutrition programs under the statute. If finalized, this rule would jeopardize the progress schools are making to provide healthier food to vulnerable children and [will] decrease the overall healthfulness of school meals,” the Center for Science in the Public (CSPI) said.

A recent study by the Robert Wood Johnson Foundation’s Healthy Eating Research program found that these proposed changes would adversely affect student’s health and academic performance and that students from low-income families attending schools are most likely to be impacted.

Virtually all schools participating in breakfast and lunch programs have made and are making great progress toward serving healthier meals for participating children with less sodium; more whole grains, fruits, and vegetables; and fewer sugary drinks and unhealthy snacks.

The current proposed rule undermines such efforts to improve the quality and nutritional value of foods served in schools. The USDA purports that the proposed changes are “customer-focused”; however, the data show that parents and students are in favor of healthier standards.

“Continually weakening the standards does not provide more stability and consistency for schools or industry. On the contrary, it continuously changes the goalposts for school efforts and industry reformulation,” Colin Schwartz, deputy director of legislative affairs for CSPI, said.

This is hardly the Trump administration’s first attempt to weaken school nutrition. It previously rolled back requirements for whole grains and sodium in kids’ meals — moves that are now the subject of two ongoing lawsuits by CSPI and partners and by a group of state attorneys general.

Global diets are converging, and that’s good news for our health and the environment

Global food trends showcase both how far we’ve come, and what problems still need to be addressed.

Image via Pixabay.

New research at the University of Kent found that diets are undergoing complex changes worldwide. The team reports that parts of the world are shifting towards healthier diets, while other areas are still experiencing malnutrition and obesity as a result of poor food access and security. The overall dynamics also have important implications for environmental sustainability, both good and bad.

What’s cooking?

“There are clear shifts in global food supply, and these trends may be responsible for strong improvements in nutrition in some parts of the world,” says Dr Bentham, co-lead author of the paper and a Lecturer in Statistics at Kent’s School of Mathematics, Statistics and Actuarial Science.

“However, obesity remains a long-term concern, and we hope that our research will open doors to analysis of the health impacts of global diet patterns. Equally, we must also consider carefully the environmental impacts of these trends.”

For the study, the team analyzed food supply data for 171 countries from the 1960s to the 2010s. They report that South Korea, China, and Taiwan have experienced the largest changes in food supply throughout that timeline, with animal-sourced foods (such as meat and eggs), sugar, vegetables, seafood, and oil crops becoming a much larger proportion of the area’s overall diet. Such a shift in diet is to be expected in developing countries, as more disposable income means people can afford more varied meals with more expensive ingredients.

On the other hand, many Western countries have seen a decline in animal-sourced foods and sugar consumption; this trend is especially noticeable in high-income English-speaking countries such as the UK, US, Canada, and Australia, they report. This is likely the product of increased public awareness of the role our diets play in our health and of the latitude to pick what we eat offered by such rich countries (a product of varied supply and high incomes). But this trend isn’t limited to the western world. Many countries around the world have seen an uptake in vegetable-based diets, the team explains.

Sub-Saharan Africa remains the worst-off of all global regions in this regard. It still lacks adequate access to a diverse food supply, which the team notes can help explain why the region is still rife with malnutrition.

Despite the limitations here, shifts towards diet adjustment in the rest of the world remain significant. The decline in consumption for animal-sourced foodstuffs and sugar and the greater availability of vegetables are very encouraging to see. Such shifts may be paving the way towards more sustainable, healthier, and more balanced diets, at least in some parts of the world. The team notes that in South Korea, China, and Taiwan in particular, the greater consumption of sugar and animal foodstuffs is correlated with a dramatic rise in obesity rates. Taken together, these findings showcase just how important diet is to public health and environmental protection efforts at the same time.

“Advances in science and technology, together with growing incomes, have allowed many nations to have access to a diversity of foods,” explains Professor Majid Ezzati from the School of Public Health at Imperial College London, the paper’s other co-lead author.

“We must harness these advances and set in place policies that provide healthier foods for people everywhere, especially those who can currently least afford them.”

The paper “Multidimensional characterization of global food supply from 1961 to 2013” has been published in the journal Nature Food.

Obesity and undernutrition now come together — over 1 in 3 poor and middle-income countries struggle with both

Many low- to middle-income countries struggle with issues of undernutrition. Around a third of them, however, are faced with a very unusual problem: undernutrition and obesity at the same time.

Obesity and undernutrition have become increasingly connected in recent decades, a new paper reports. It explains that modern food systems are negatively impacting the health of poorer countries around the world, with the poorest being particularly affected. The authors also look at the causes, context, and possible solutions to this issue.

The faults in our food

“We are facing a new nutrition reality where major food system changes have led the poorest countries to have high levels of overweight and obesity along with undernutrition,” says Barry M. Popkin, lead author of the paper and W.R. Kenan Jr. Distinguished Professor of Nutrition at the University of North Carolina.

“Our research shows that overweight and obesity levels of at least 20% among adults are found in all low-income countries. Furthermore, the double burden of high levels of both undernutrition and overweight occurs primarily in the lowest-income countries — a reality that is driven by the modern food system. This system has a global reach and is preventing low- and even moderate-income countries and households from consuming safe, affordable, and healthy diets in a sustainable way.”

Global estimates place the total number of obese children and adults in the world at some 2.3 billion, the paper explains. It’s just one half of the issue known as the double burden of malnutrition — the other being undernutrition, a deficiency of calories or (in this context) essential nutrients.

For the study, the team used survey data from low- and middle-income countries in the 1990s and 2010s to estimate which of them were experiencing the double burden of malnutrition. If over 15% of a country’s population had wasting and over 30% stunting, over 20% of its women show thinness, and over 20% of its citizens in total were overweight, the team considered that particular country to be experiencing this double burden.

Over a third of low- and middle-income countries satisfy this condition — 45 of 123 countries in the 1990s and 48 of 126 countries in the 2010s — meaning they’re experiencing both forms of malnutrition. It was most commonly seen in sub-Saharan Africa, East Asia and the Pacific, and South Asia where 29, 9, and 7 countries were affected, respectively. In the 2010s, 14 more countries (with some of the lowest incomes in the world) had started to experience this double burden of malnutrition compared to the 1990s.

In comparison, low- and middle-income countries that enjoy the highest incomes in the category were much less likely to experience this issue, the team adds. In their view, this is indicative of a growing number of overweight people in the poorest countries even as large segments of the population face stunting, wasting, and thinness.

“Emerging malnutrition issues are a stark indicator of the people who are not protected from the factors that drive poor diets,” Popkin says. “The poorest low- and middle-income countries are seeing a rapid transformation in the way people eat, drink, and move at work, home, in transport, and in leisure.”

“The new nutrition reality is driven by changes to the food system, which have increased the global availability of ultra-processed foods that are linked to weight gain while also adversely affecting infant and preschooler diets. These changes include disappearing fresh food markets, increasing numbers of supermarkets, and the control of the food chain by supermarkets and global food, catering, and agriculture companies in many countries.”

But how can someone be both underfed and overfed at the same time? It comes down to the quality of food they can access. Ultra-processed foods are a very attractive option for people with low incomes, as they’re convenient (they require very little time investment to prepare), they seem hearty and are widely available. However, while they usually pack a caloric punch, they’re very poor in nutrients; in essence, they’re empty calories. Even worse, they usually contain a high level of additives to make them more appealing and to increase shelf-life, which can have adverse effects on health and body mass.

In an ironic twist of fate, healthy options such as fresh vegetables can be effectively out of reach for people with low incomes who may not have the purchasing power or time necessary to acquire and prepare them, or simply haven’t been educated on the drawbacks of their current diet.

The authors recommend “double-duty” policies aimed at reducing both the risk of nutritional deficiency and that of obesity and its related effects. They call for a concentrated effort from local governments, civil society, academia, the private sector, and the United Nations to create the economic conditions needed to address the double burden of malnutrition to devise and implement such strategies.

We also shouldn’t make the error of believing this issue is limited solely to ‘someplace else’. Previous research has highlighted that over half of America’s calories come from ultra-processed foods, and that they are responsible for 90% of the total added sugar intake in the country.

The paper “Dynamics of the double burden of malnutrition and the changing nutrition reality” has been published in the journal The Lancet.

More than 70% of America’s packaged food is ultra-processed — and it’s a big problem

The food supply in the US is dominated by ultra-processed foods which are almost always high in energy, saturated fat, sugar, and salt.

Avoid ultra-processed foods, physicians warn. Image credits: FDA.

Unhealthy processed food

For every 10 calories someone in the US eats, 8 come from store-bought foods and beverages (packaged and unpackaged). The ready-to-eat food market plays a crucial role in the US, and it also plays a crucial role in the development of obesity and cardiovascular diseases.

Time and time again, studies have shown that processed foods (and particularly, ultra-processed foods) are dangerous to human health. Not only do they make you fat, but they also increase the risk of many serious conditions, including cancer and diabetes — and yet, Americans can’t have enough of them.

“The US packaged food and beverage supply is large, heterogeneous, highly processed, and generally unhealthy,” the new study reads.

Scientists analyzed 230,156 products, finding that 71% of products such as bread, salad dressings, snack foods, sweets, sugary drinks and more were ultra-processed. When they looked at the largest 25 manufacturers, a whopping 86% of products were classified as ultra-processed.

Scientists also ranked foods based on their healthfulness, using a ranking system developed in Australia that ranks foods from 0.5 stars (unhealthiest) to 5 stars (healthiest) The Health Star Rating system scores packaged foods, offering consumers a quick look at the nutritional profile of packaged foods — something which can be difficult to assess in our day to day lives.

What’s ultra-processed anyway?

A decision we’ve all had to make countless times — what did you choose? Image credits: US Air Force.

The way we eat has changed substantially in the past few decades.  When early dietary guidelines were compiled and published in the first half of the last century, the vast majority of foods was sold as ingredients to be combined and consumed in the form of dishes or meals, or eat as it is. But after the 1950s, things started to change. More and more, we had access to pre-packaged, branded, and ready-to-eat (or drink) food. This was seen as more convenient and became increasingly prominent in high-income countries. But not long after that, it became clear that foods purchased this way aren’t healthy at all.

Although processed foods don’t need to be unhealthy, in practice, they almost always are. This is why the NOVA classification for food was devised, to help people understand what’s processed and what’s not. Here are the main categories:

  • unprocessed or minimally processed foods (think seeds, fruits, vegetables, eggs, etc);
  • processed culinary ingredients (flour, butter, vegetable oils, etc);
  • processed foods (relatively simple foods prepared with 2-3 ingredients — think canned beans or sugared nuts);
  • ultra-processed foods (complex foods that typically have many ingredients including sugar, oils, fats, salt, stabilizers, and preservatives — think foods like ice cream, cakes, sodas, burgers, sausages, nuggets, pastries, energy bars, and many many more).

Ultra-processed foods are unhealthy no matter where you look but compared to other countries, the US version is even worse, because it is generally processed with a higher sugar and sodium content, the study reports.

While the study did not analyze 100% of the market, it analyzed data collected by the Chicago company Label Insight, which represents more than 80% of all food and beverage products sold in the US over the past three years — enough to paint a comprehensive picture.

“We need to better capture real-time information of our constantly changing food supply if we’re going to track and improve its healthfulness,” said study co-author Dr. Mark Huffman, the Quentin D. Young Professor of Health Policy, associate professor of preventive medicine and medicine at Feinberg and a Northwestern Medicine cardiologist.

The fact that the average American has an unhealthy diet isn’t really a surprise by now. However, it’s important to understand the scale of the problem and reduce it as much as possible.

“To say that our food supply is highly processed won’t shock anyone, but it’s important that we hold food and beverage manufacturers accountable by continually documenting how they’re doing in terms of providing healthy foods for consumers,” said lead author Abigail Baldridge, a biostatistician in the department of preventive medicine at Northwestern University Feinberg School of Medicine. “And the verdict is they can and should be doing a whole lot better.”

The study was published in the journal Nutrients.


This small change could cut halve your diet’s environmental impact

A simple change could massively reduce the negative impact of most people’s diets: swapping beef for poultry.

Bottom line: don’t eat this guy.

It doesn’t often make the headlines, but food production is one of the major culprits of climate change, contributing up to 29% of total greenhouse gas emissions. Out of this, meat takes an overwhelming slice of the pie.

At a basic level, it’s easy to understand why meat is so inefficient: plants convert around 10% of the energy they receive into edible nutrients. Animals have a similar rate: only about 10% of the plants they eat are converted into something we can eat, so 90% of the energy is wasted (arguably, some of that energy comes from plants we ourselves couldn’t eat, but even so, it’s a wasteful process).

Over 50% of all the emissions associated with food comes from meat production and consumption, although meat itself provides less than 10% of the calories we eat. Beef, in particular, is extremely inefficient.

A beef with the environment

It takes 75 times more energy to produce a pound of beef than to produce a pound of corn, and beef also requires 54 calories of fuel to produce 1 calorie of protein, compared to 2-3 calories of fossil fuel for 1 calorie of soy or wheat. Study after study has shown that beef is an important contributor to global greenhouse gas emissions — and this one is no different. In the latest research, scientists show that even by replacing beef with other meat (poultry) it could make a big difference.

Diego Rose, a director of nutrition at Tulane University, analyzed what would happen if people would substitute a beef-focused meal with a similar poultry meal. Along with his colleagues, he analyzed the diet information from more than 16,000 participants in the 2005-2010 National Health and Nutrition Examination Survey, calculating a carbon footprint of all diets.

They found that the 10 foods with the highest impacts on the environment were all cuts of beef.

Then, they looked at what would happen if all beef in the diets would be replaced by an equivalent poultry dish. For instance, broiled beef steak was replaced with broiled chicken and ground beef with ground turkey. The results were impressive.

“Our simulation showed that you don’t have to give up animal products to improve your carbon footprint,” Rose commented on the study. “Just one food substitution brought close to a 50% reduction, on average, in a person’s carbon footprint.”

That’s how disproportionate beef’s carbon footprint is — even replacing it for something that’s not exactly eco-friendly either has a massive impact. Of course, any further reduction of meat consumption has even more environmental benefits. Researchers also stress that food waste and overeating also increase the carbon footprint of our diet.

The results have not yet been peer-reviewed but have been presented at the Nutrition 2019 conference, where they have been selected by a panel of experts.



Not eating enough fruits and veggies kills millions of people every year

The preliminary results of a major new study show that about 1 in 7 cardiovascular deaths could be attributed to not eating enough fruit and 1 in 12 cardiovascular deaths could be attributed to not eating enough vegetables.

The bottom line — you should probably eat more fruits and vegetables.

Your mom was probably right: you should eat more fruits and veggies — you and millions of other people. Fruits and vegetables are an essential part of a healthy diet, serving as an excellent source of fiber, potassium, magnesium, antioxidants — all of which have been shown to improve health. They’re also associated with a lower incidence of obesity and diabetes, which also carry multiple health risks.

A new study finds that insufficient intake of fruits and veggies is responsible for around 23% of all cardiovascular (CVD) fatalities. Low fruit intake was associated with nearly 1.8 million cardiovascular deaths in 2010, while low vegetable intake was associated with 1 million deaths, according to researchers. In terms of both fatalities and intake, the toll of insufficient fruit consumption was double than that of vegetables.

“Fruits and vegetables are a modifiable component of diet that can impact preventable deaths globally,” said lead study author Victoria Miller, a postdoctoral researcher at the Friedman School of Nutrition Science and Policy at Tufts University. “Our findings indicate the need for population-based efforts to increase fruit and vegetable consumption throughout the world.”

Nutrition is extremely complex and often times, studies can sometimes seem contradictory, but the science has been remarkably consistent when it comes to fruits and vegetables: they’re good for you. Replacing them with processed foods, or things like meat and dairy, often has substantial and long-lasting negative effects. The study authors call for increased availability and promotion of fruits and vegetables, so that people can be encouraged to incorporate more of them into their diet.

“Global nutrition priorities have traditionally focused on providing sufficient calories, vitamin supplementation and reducing additives like salt and sugar,” said senior study author Dariush Mozaffarian, dean of the Friedman School of Nutrition Science and Policy at Tufts University. “These findings indicate a need to expand the focus to increasing availability and consumption of protective foods like fruits, vegetables and legumes–a positive message with tremendous potential for improving global health.”

So how much fruits and veggies should you eat?

In the United States, suboptimal vegetable intake may account for 82,000 cardiovascular deaths while suboptimal fruit intake may account for 57,000 deaths. Cardiovascular disease is the number one cause of death in the United States and worldwide. Image credits: Global Dietary Database 2010/Friedman School of Nutrition Science & Policy at Tufts University.

The dietary guidelines vary slightly from country to country, but they all seem to hover around 300 grams per day for fruit consumption — the equivalent of about two apples. Meanwhile, veggie consumption should come at 400 grams per day — about three carrots (this includes all fruits and vegetables, including legumes).

Naturally, the impact of insufficient fruit and vegetable consumption was greatest where the consumption was lowest. Countries like the US, India, and several countries in Eastern Europe have a higher impact than places such as China or Western and Northern Europe.

There were also important differences based on age groups, seeming to disproportionately affect younger adults. Men were also more affected, presumably because women tend to eat more fruits and vegetables.

The findings have not been peer-reviewed and will be presented at the Nutrition 2019 conference, where they were selected by a committee of experts. This is the most comprehensive study of its kind to date.

“Inadequate fruit and vegetable intake contributes to cardiovascular diseases (CVD), and the impacts of fruits and vegetables on CVD risk worldwide has not been well established by country, age, and sex. Our objective was to derive comprehensive and accurate estimates of the burdens of CVD attributable to fruit and vegetable consumption using the largest standardized global dietary database currently available,” the study’s abstract reads.

The results paint a worrying picture, but there is also some good news: increasing consumption of fruits and veggies is, at least in theory, pretty easy. Each and every one of us can make this decision every day. Increasing consumption at a wider scale, which is what researchers are suggesting, remains much more challenging, but a thorough assessment is the first step.


Eggs might not be that bad for you after all, new study finds

A new study finds that a consumption of up to one egg a day does not increase the risk of stroke.

Eating boiled eggs is substantially healthier than fried or scrambled.

Eggs are somewhat of an unsettled issue in modern nutrition: on the one hand, they have a wealth of valuable nutrients, but on the other hand, they also contain cholesterol and have been traditionally regarded as hazardous for cardiovascular health. Eggs have remained a controversial issue, with studies often finding contradictory results.

Now, a new effort finds that in low quantities (about 1 per day), eggs don’t seem to have any detrimental effect on the heart or blood pressure. In fact, there was a small inverse correlation between blood pressure and egg consumption.

The study analyzed the dietary habits of 1,950 Finnish men between 42 and 60 years old with no history of cardiovascular disease. The study also looked at carriers of a particular protein called E phenotype 4. This protein combines with fats (lipids) in the body to form molecules called lipoproteins. Lipoproteins are responsible for packaging cholesterol and other fats and delivering them through the bloodstream. People who carry this hereditary variant are particularly vulnerable to the effects of cholesterol. Finnish people are unusual in this regard: their prevalence of this variant is exceptionally high, affecting around 1 in 3 people. Presumably, if eating one egg a day would cause heart issues, you’d see it in this population first.

However, the study found that moderate egg consumption, even daily, does not seem to be associated with greater risk of stroke — even in people who are predisposed to the effects of cholesterol. While this is encouraging news for egg-lovers, it also shouldn’t be generalized: it all greatly depends on your total cholesterol intake (in this study, eggs represented an overall 25% of total cholesterol consumption). If your diet is rich in cholesterol and fats, then egg consumption can be the proverbial straw that breaks the camel’s back. Furthermore, the generalizability of this study is also weakened fact that the population in this study had no cardiovascular conditions or diseases, researchers say.

Nutrition is an amazingly complex topic, and eggs, in particular, are far from a settled issue. As it is so often the case, maintaining a balance is key. Overall, the research seems to indicate that, at least in a healthy diet, eggs can play a useful and important role. In other words, as long as you don’t eat too many saturated fats (butter, cheese, meats), you’ll probably be okay.

Journal Reference: Abdollahi et al. Egg consumption, cholesterol intake, and risk of incident stroke in men: the Kuopio Ischaemic Heart Disease Risk Factor Study. The American Journal of Clinical Nutrition, 2019; DOI:10.1093/ajcn/nqz066

Ultra-processed foods cause weight gain, over eating, according to a new study

A preliminary study reports that eating ultra-processed leads to eating more calories and weight gain.

Instant Noodles.

Image via Pixabay.

People who eat ultra-processed foods have a higher calorie intake and gain more weight compared to those who eat a minimally-processed diet, a new study from the National Institutes of Health reports. This difference, the team explains, was seen even when participants in the ultra-processed and minimally-processed diet groups received the same number of calories and macronutrients in their food.


“Though we examined a small group, results from this tightly controlled experiment showed a clear and consistent difference between the two diets,” said Kevin D. Hall, Ph.D., an NIDDK senior investigator and the study’s lead author.

“This is the first study to demonstrate causality — that ultra-processed foods cause people to eat too many calories and gain weight.”

The study, at the NIH’s National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), was small-scale — it only included 20 adult volunteers. The authors report that it is the first randomized trial meant to look into the effects of ultra-processed foods as defined by the NOVA classification system. Previous observational studies, they explain, worked with large groups of people and have uncovered an association between diets with high amounts of processed food and health complications. However, these efforts had been randomized, so they can’t be used to establish a clear link between the two (people might have experienced health complications due to other factors, such as lack of access to fresh food, not necessarily from ultra-processed ones).

Under the NOVA system, foods that have ingredients predominantly found in industrial food manufacturing, such as hydrogenated oils, high-fructose corn syrup, flavoring agents, and emulsifiers, are considered to be “ultra-processed”.

“Results from this tightly controlled experiment showed a clear and consistent difference between the two diets,” said Kevin D. Hall, Ph.D., an NIDDK senior investigator and the study’s lead author. “This is the first study to demonstrate causality — that ultra-processed foods cause people to eat too many calories and gain weight.”

The participants, 10 male and 10 female, were admitted to the NIH Clinical Center for one continuous month. They were placed on each diet for two weeks (in random order), the team providing them with meals consisting of either ultra-processed or minimally processed foods. An ultra-processed breakfast, for example, might consist of a bagel, cream cheese, and turkey bacon, while the unprocessed breakfast was oatmeal with bananas, walnuts, and skim milk. Meals in both courses were controlled to have the same amounts of calories, sugars, fiber, fat, and carbohydrates. Participants were allowed to eat as much as they wanted.

People on the ultra-processed diet ate about 500 calories more per day than those on the unprocessed one. They also ate faster and gained weight, whereas their counterparts lost weight. On average, participants in the ultra-processed group gained 2 pounds (0.9 kilograms) and lost an equivalent amount on the unprocessed diet. “We need to figure out what specific aspect of the ultra-processed foods affected people’s eating behavior and led them to gain weight,” Hall admits. For example, the team says that slight differences in protein levels between the ultra-processed and unprocessed diets used in the study could explain up to half of the difference in caloric intake between the two groups.

“The next step is to design similar studies with a reformulated ultra-processed diet to see if the changes can make the diet effect on calorie intake and body weight disappear,” Hall explains.

“Over time, extra calories add up, and that extra weight can lead to serious health conditions,” said NIDDK Director Griffin P. Rodgers, M.D. “Research like this is an important part of understanding the role of nutrition in health and may also help people identify foods that are both nutritious and accessible — helping people stay healthy for the long term.”

While the study reinforces the benefits of unprocessed foods, researchers note that ultra-processed foods can be difficult to restrict. “We have to be mindful that it takes more time and more money to prepare less-processed foods,” Hall said. “Just telling people to eat healthier may not be effective for some people without improved access to healthy foods.”

The paper “Ultra-Processed Diets Cause Excess Calorie Intake and Weight Gain: An Inpatient Randomized Controlled Trial of Ad Libitum Food Intake” has been published in the journal Cell Metabolism.

Eating processed food linked to eating too much and being overweight

A new study confirms a long-standing theory of nutrition science: processed food really makes you eat more.

This image shows one of the study’s processed lunches, consisting of quesadillas, refried beans, and diet lemonade. Image credits: Hall et al./Cell Metabolism.

Some researchers have long thought that eating processed food leads to overeating, but separating individual factors like this is hard to do because comparing dietary habits is notoriously complicated. However, in the new study, researchers were able to show that even when two diets were matched for the amount of carbohydrates, fat, sugar, salt, and calories — people consumed more food and gained weight on an ultra-processed diet.

“I was surprised by the findings from this study, because I thought that if we matched the two diets for components like sugars, fat, carbohydrates, protein, and sodium, there wouldn’t be anything magical about the ultra-processed food that would cause people to eat more,” says lead author Kevin Hall, a section chief in the Laboratory of Biological Modeling at the National Institute of Diabetes and Digestive and Kidney Diseases within the National Institutes of Health. “But we found that, in fact, people ate many more calories on the ultra-processed diet, and this caused them to gain weight and body fat.”

The study enrolled 20 healthy (an important limitation of this study is its small sample size). Each participant was given either an ultra-processed diet or an unprocessed diet for two weeks. The meals were then switched. The volunteers were given three meals a day and had access to bottled water and either ultra-processed or unprocessed snacks throughout the day. They were instructed to eat as much as they want.

Meanwhile, researchers measured the quantities of consumed food.

The scale of the difference was shocking: during the two weeks that they were given ultra-processed food, participants consumed an average of 508 calories more per day, compared with the days they got unprocessed food. For reference, an average woman needs to eat about 2000 calories per day to maintain, and an average man needs to eat about 2500 calories.

This image shows one of the study’s unprocessed lunches, consisting of a spinach salad with chicken breast, apple slices, bulgur, sunflower seeds, and grapes. Image credits: Hall et al./Cell Metabolism.

Participants gained, on average, 2 pounds (0.9 kg) during the two weeks of processed food, but lost them in the unprocessed diet weeks. Body fat exhibited a similar trend, growing during the processed food weeks and dropping during for the unprocessed diet.

Researchers also noticed another interesting trend: when people were on the processed diet, they ate faster.

“There may be something about the textural or sensory properties of the food that made them eat more quickly,” Hall also adds. “If you’re eating very quickly, perhaps you’re not giving your gastrointestinal tract enough time to signal to your brain that you’re full. When this happens, you might easily overeat.”

It’s not fully clear why these differences were observed. It could be that, as Hall speculates, the speed of eating is very important. Another hypothesis refers to the role of solid foods versus beverages. In order to match the calorie and dietary fiber intake, researchers had to add lemonades and juices to the ultra-processed meals. These juices were “spiked” with dietary fiber since processed foods tend to be extremely poor in fibers. However, even though the nutritional content was perfectly matched, some researchers believe that beverages don’t offer the same satiety as solid foods. So people might have not felt as full and might have been more inclined to overeat on the processed diets.

A third factor could be that although the diets were matched as closely as possible, the unprocessed diet contained slightly more protein, about 15.6% of calories versus 14% for the ultra-processed diet. “It could be that people ate more because they were trying to reach certain protein targets,” Hall speculates.

Regardless of the reason, this is one of the first studies to directly show that processed food can lead to overeating. Ultra-processed foods have been linked to a multitude of health problems, from gut conditions to cancer. We need to be mindful of what we eat, researchers urge. A healthy diet involves lots of fruits and veggies, low quantities of sugar and processed foods.

“We know there are a lot of factors that contribute to why someone might choose an ultra-processed meal over an unprocessed one,” Hall says. “For people in lower socio-economic brackets especially, we need to be mindful of the skills, equipment, knowledge, and expense needed to create unprocessed meals.”

Journal Reference: Cell Metabolism, Hall et al.: “Ultra-processed diets cause excess calorie intake and weight gain: An inpatient randomized controlled trial of ad libitum food intake”

New ‘brain training’ game could help you wean off of excess added sugar

Researchers at Drexel University, Pennsylvania want to help you cut down on excessive sugar consumption by playing a game.


Image via Pixabay.

The U.S. Department of Health and Human Services estimates that over half of American adults consume excessive amounts of added sugars, with detrimental effects to their health. A new study led by Evan Forman, Ph.D., a psychology professor at Drexel University’s College of Arts and Sciences, reports that computer games can be used to train players to wean off this sugar and help them to improve their health and manage their weight more easily.

Too sweet

“Added sugar is one of the biggest culprits of excess calories and is also associated with several health risks including cancer,” said Forman, who also leads the Center for Weight, Eating and Lifestyle Science (WELL Center) at Drexel.

“For these reasons, eliminating added sugar from a person’s diet results in weight loss and reduced risk of disease.”

The team developed and tested the efficiency of a “brain training game” that targets the brain area which inhibits our impulses. The aim was to train people to better resist the lure of foods with added sugars, specifically to decrease the consumption of sweets and sweet foods. Such systems have shown their efficiency in helping people quit other unhealthy habits, such as smoking. Forman says that this study is the first to look at how “highly personalized and/or gamified inhibitory control training” can help with weight loss using repeated, at-home training sessions.

In collaboration with Michael Wagner, a professor and head of the Digital Media department in Drexel’s Westphal College of Media Arts & Design and a group of digital media students, the team developed a game they named “Diet DASH”.

Diet DASH is built to integrate with each player’s particular habits. It automatically customized itself to focus on the sweets each participant tended to eat and adjusted its difficulty according to how well each player was resisting the temptation to eat said sweets. To test how well it worked, the team collaborated with a randomized group of 109 participants who were overweight and reported to over-enjoy sweets. Prior to starting the game, each participant took part in a workshop to help them understand why sugar is detrimental to their health and to learn which foods to avoid and methods for doing so.

“Prior to randomization, all participants attended a 2-h workshop in which they were provided with a dietary prescription (to eat only foods without added sugar or with very low amounts of added sugar, such as certain low-sugar breakfast cereals) as well as guidance in making dietary
modifications (e.g., reading food labels, shopping and cooking substitutions). Explanatory text, figures, and tables that allowed participants to easily identify targeted foods with added sugar were distributed,” the paper explains.

“The workshop helped give participants strategies for following a no-sugar diet. However, we hypothesized that participants would need an extra tool to help manage sweets cravings,” said Forman. “The daily trainings could make or break a person’s ability to follow the no-added sugar diet. They strengthen the part of your brain to not react to the impulse for sweets.”

Game screenshot.

Image credits Evan M. Forman et al., (2019), JoBM.

Each participant played the game for a few minutes every day for six weeks and then once a week for two weeks. The game itself places players in a grocery store, with the goal of putting the correct (healthy) food in a grocery cart as fast as possible while refraining from choosing incorrect food (their preferred sweets). Players were awarded points for correct items placed in carts.

Participants were randomly assigned to a highly-gamified version of the game (with better graphics and sounds) or a less-gamified version. The team reports that the gamification level didn’t seem to matter much as far as weight loss was concerned. However, the (few) male participants in the study reacted better to the highly gamified version than the women in the study.

Over half the participants in the study showed higher preferences toward sweets. For this group, the game helped them lose as much as 3.1% of their total body weight over eight weeks. Participants also rated how satisfactory they found the daily training, whether or not it became part of their daily routine, and whether they wished to continue with the training if it becomes publicly available.

“The study’s findings offer qualified support for the use of a computerized cognitive training to facilitate weight loss,” said Forman.

The WELL Center is now conducting a new trial with the highly gamified version of this training program specifically for men and is actively recruiting participants.

The paper “Computerized neurocognitive training for improving dietary health and facilitating weight loss” has been published in the Journal of Behavioral Medicine.

Going vegan might not be the greenest diet — but giving up meat, is

Giving up on meat (particularly red meat) is definitely one of the most eco-friendly things you can do, but going the extra mile and turning vegan might not be as rewarding, new research finds.

Vegan or vegetarian, it makes little difference — at least from a land usage perspective.

The world sure loves meat. As of 2018, the average American adult eats 222.2 pounds of meat and poultry per year, which, aside from ethical considerations, also comes with a lot of water consumption and greenhouse gas emissions. What all this is saying, essentially, is that meat consumption places a massive stress on the environment — and if we want to reduce our environmental impact, eating less meat seems crucial.

In order to assess the environmental cost of various low-meat diets, a team of researchers used a biophysical simulation and compared 10 different eating patterns: the vegan diet, two vegetarian diets (one that only includes dairy, and another that includes both dairy and eggs), four omnivorous diets (with various levels of plant and meat consumption), one low in fats and sugars, and lastly, a diet that’s very similar to the average eating standards in the US (high in meat, sugars, and processed foods).

The researchers looked at how much land use was associated with each particular diet — which is an additional concern to water and greenhouse gases. They found that counter-intuitively, the vegan diet wasn’t the most eco-friendly choice — it was outmatched by both vegetarian diets, as well as two omnivorous diets with low meat consumption. Again, this is only about land usage.

The reason for this has a lot to do with agriculture. We use different types of soils to grow different types of foods, and when you’re following a vegan diet, you basically forego a set of environmental conditions. For instance, some areas may be unsuited for agricultural plants, but are ideal for grazing, which can be used for cattle in the dairy industry.

[panel style=”panel-default” title=”Vegan myths” footer=””] There are many myths surrounding vegetarianism and veganism — probably the more prevalent is that you can’t get enough protein without meat. However, that’s hardly the case. There are many options to substitute meat consumption, and vegetarian/vegan diets can be just as nutritious (and even healthier) if they are carefully planned.[/panel]

The ten eating patterns clearly developed into two groups: the diets which featured the highest meat consumption also required the most amount of land. But in the group with lower or no meat consumption, things weren’t as clear-cut. The vegan diet particularly stands out because it doesn’t use any perennial land at all — in other words, the lands that grow hay or grain used to feed livestock are essentially wasted.

Perennial crops also offer another advantage, surviving for many seasons and reducing the agricultural “wear and tear” on the environment. To put it simply, veganism is a strict diet, which renders a lot of otherwise usable land useless, which limits some of its environmental advantages.

Image credits: Peters et al / Elementa.

However, the scale of the difference is important to underline. The differences between the vegan and two vegetarian diets are minute — but as soon as the meat consumption increases, the land usage increases dramatically, particularly due to all the land needed for grazing. Simply put, the vegan-vegetarian differences were marginal — but the vegetarian/vegan-meat differences are huge.

Of course, there’s an argument to be made against this type of utilitarian approach — many vegans choose this diet for ethical reasons, and would (rightly) not be swayed by this sort of argument. But this also shouldn’t be a reason to not go vegan. The downside of the vegan diet emerges only if everyone adopts it, which realistically speaking, won’t happen anytime soon. Even if the number of vegans grows dramatically year after year, there would still be a significant demand for animal products, so this study should deter no would-be vegans.

At the end of the day, the important takeaway is that no matter what your dietary preferences are, you should, at any rate, try to reduce meat consumption. It’s better for the animals, it’s better for the land, for the planet, and as countless studies have already shown, it’s better for you.

The study has been published in the journal Elementa.

Eating before going to sleep might not be all that bad, researchers find

Traditional wisdom says that you shouldn’t eat before going to sleep, but a new study casts doubt on that belief.

Late night snacks might not be all that bad, a new study concludes. Image in public domain.

A lot of changes happen in our bodies when we sleep. Among other things, our metabolism and digestion slow down. It seems quite logical, therefore, that you shouldn’t eat before going to sleep — otherwise, your body just doesn’t have enough time to process it all and your blood sugar increases.

This translates into a common piece of advice which has been adopted into many cultures: “Don’t eat two hours before bedtime.” However, a new study casts new doubt on this advice, finding no clear connection between eating before bedtime and blood sugar levels.

Su Su Maw and Chiyori Haga, two researchers from Okayama University assessed the effect of pre-sleep eating. They analyzed 1,573 healthy middle-aged and older adults with no underlying conditions, looking at the levels of HbA1c — the most common marker for blood glucose (sugar) levels for the last two to three months. A high HbA1c means you have too much sugar in your blood (which in turn, means you’re more likely to develop serious health issues like diabetes).

In all, 83 (16%) of the men and 70 (7.5%) of the women fell asleep within 2 hours of eating dinner. However, when they corrected for other factors (such as smoking, overall weight, blood pressure, etc) they did not find any connection between the two.

Instead, researchers find that lifestyle choices like drinking or smoking are the leading factors when it comes to blood sugar levels. They also emphasize that eating nutritious foods and maintaining a healthy lifestyle are actually more important than eating before bedtime. Simply put, what you eat is much more important than when you eat.

“Contrary to general belief, ensuring a short interval between the last meal of the day and bedtime did not significantly affect HbA1c levels,” researchers write.

“More attention should be paid to healthy portions and food components, getting adequate sleep and avoiding smoking, alcohol consumption, and overweight, as these variables had a more profound influence on the metabolic process.”

However, it should be noted that the study was carried out in Japan, where afternoon portions are relatively small and often contain healthy foods such as soup or vegetables, so the findings might not translate to other diets and countries.

At any rate, this doesn’t mean you should go crazy with the late snacks. Ice cream and French fries are still probably not okay.

Journal Reference: Su Su Maw and Chiyori Haga. Effect of a 2-hour interval between dinner and bedtime on glycated haemoglobin levels in middle-aged and elderly Japanese people: a longitudinal analysis of 3-year health check-up data. BMJ Nutrition, Prevention & Health, 2019 DOI: 10.1136/bmjnph-2018-000011

The planetary diet: here’s what you need to eat to save the planet

As the world prepares for a population of 10 billion people, we are faced with the fact that our eating habits are unsustainable and need to be changed. Researchers have now proposed a healthy and diverse diet which can accommodate this huge number of people and is available to a wide range of geographies and budgets.

If we want to feed 10 billion people, we need more of this in our lives. But then again, it doesn’t look so bad does it? Image credits: Dana Tentis.

We don’t often think about it, but all our food comes from somewhere — it uses resources such as land and water, it needs to be transported, stored, and so on. Some foods are better than others, needing fewer resources and maintenance — often times, these are also the foods which are healthier for us. With this in mind, a team of researchers set out to develop a so-called planetary diet — a diet which doesn’t only focus on the people but also on the planet.

The diet was designed by the EAT-Lancet commission, comprised of experts from the Norway-based thinktank Eat and the British journal the Lancet. The team boasts world-leading researchers in nutrition, health, farming, sustainability and policy from across the world. Together, they spent two years on this project, creating guidelines that can feed 10 billion people, ensure that habitat destruction is reduced, minimize greenhouse gas emissions and save water.

So what should you eat?

If you like meat — that’s the first problem. It’s not like you can’t eat meat at all, but one burger or big steak a week is pretty much it. Worldwide, livestock accounts for between 14.5 and 18% of human-induced greenhouse gas emissions, and it also requires vast areas of land. You can sneak in a couple of portions of chicken and fish every week though, and you get to drink a glass of milk (or a couple of cheese slices every day) — but the rest needs to come from plants.

Fruit and vegetables should make about half of what’s on our plates. However, we should place less emphasis on starchy vegetables such as the potato or cassava, which is very popular in Africa.

The good news is that you can easily get all your necessary protein and carbs with a planetary diet, and it features substantially more fiber than most of us eat, which is excellent for your health. Here’s an example of what an average day’s diet would comprise:

  1. Nuts – 50g a day;
  2. Beanschickpeaslentils and other legumes – 75g a day;
  3. Fish – 28g a day;
  4. Eggs – 13g a day (so 2 medium eggs a week);
  5. Meat – 14g a day of red meat and 29g a day of chicken (more likely, this would be compressed into a portion every week);
  6. Carbs – whole grains like bread and rice 232g a day and 50g a day of starchy vegetables;
  7. Dairy – 250g – the equivalent of one glass of milk;
  8. Vegetables – (300g) and fruit (200g);

Here’s the thing: there’s a great deal of variety in this. You can take all these foods and put them together in numerous different and tasty dishes — and this is only an example. You can easily devise a great variety of nutritious and delicious foods. Here are just a few examples:

A nutritious and eco-friendly breakfast. Image in public domain.


  • The simplest choice would be milk & cereal or granola, with some nuts and fruits;
  • Whole wheat toast with jam or fruits;
  • Rice pudding with fruit syrup;


  • Whole bread sandwiches with cheese, lettuce, and tomato (maybe a slice of ham or chicken);
  • A bean and rice chili, with peppers and veggies;
  • Mushroom risotto with a vegetable stir-fry;
  • You have five meat servings over the week (one meat, two fish, two chicken). Of course, you can substitute these around, and say have six chicken servings over the week and only one meatless day. However, reducing meat consumption is one of the keys of this diet.


  • Whole wheat pasta would be a very strong contender — and as we all know, there’s a million ways to make pasta. Go easy on the meat and cheese, and you’re good to go;
  • Salads are another good idea, and they don’t need to be green leafy salads either — mix in some carrots, apples, or even a bit of fish;
  • A warming curry with lentil and green beans;
  • Cauliflower cheese.

Cut down food waste

The diet is extremely varied — you can create countless tasty recipes. Image in public domain.

However, this is only the first step, and we also need to work on the other end: food waste. The Eat-Lancet emphasizes that we need to drastically curb our food waste. Considering that 2 billion people are micronutrient deficient, and almost 1 billion go hungry — while 2.1 billion adults are overweight or obese, the problem is easy to understand. We waste an ungodly amount of food (approximately 1.3 billion tonnes every year), and that needs to be reduced drastically.

Furthermore, this approach would also make the world much healthier. Unhealthy diets are, the report says, have become “the largest global burden of disease”, posing a greater threat than “unsafe sex, alcohol, drug, and tobacco use combined.”

Most importantly, these foods (or readily available alternatives) are found all over the world. Of course, something that is available in Washington D.C. might not be easy to find in Paris or Rio de Janeiro. Having adaptable foods is the crux of this approach, which is not a strict diet, but rather a lifestyle which is better for you and better for the planet.

The world is soon nearing a decisive moment. With global warming reaching catastrophic levels, with a growing population and an ever-increasing strain on the planet’s resources, we need to find a way to feed the world sustainably. If that means giving up on meat and potatoes every once in a while, you can count me in.

There’s no such thing as an ideal diet, new study suggests

As long as you keep a healthy balance and an active lifestyle, things should generally be okay.

A Tsimane member. Image credits: jambogyuri.


In modern times, diet studies are often confusing or even contradictory — some diets focus on proteins, others say you should eat more carbs, others emphasize fruits and veggies, there’s probably a diet for every imagination. But while some things are pretty clear by now (fruits and veggies are good, processed meats are bad), others are hotly debated.

Scientists have long debated whether there’s an ideal food diet, something that we as a species evolved to eat. A team of researchers explored that question by studying the diets, habits and physical activity levels of hundreds of modern hunter-gatherer groups and small-scale societies. These groups have a very similar lifestyle that of ancient human societies.

Right off the bat, there were major differences between these groups. Some groups got up to 80% of their calories from carbohydrates, while others got most of their energy from protein. Some groups such as the Hadza people in Tanzania eat a large amount of sugar in the form of honey, deriving over 15% of their calories from honey (which, for most practical purposes, is similar to sugar).

If anything, the common denominator is diversity.

“Diets in hunter‐gatherer and other small‐scale societies tend to be less energy dense and richer in fibre and micronutrients than modern diets but are not invariably low carbohydrate as sometimes argued,” researchers write.

A complex picture

In any given day, the Hadza eat red meat and honey, but also potato-like roots — not exactly what you’d imagine as a very healthy diet. Meanwhile, the Tsimane, a Bolivian population, eat more complex carbohydrates from plantain, corn, cassava, rice and banana, often complemented by fish and wild game. The percentage of different nutrients varies wildly, but the health effects seem negligible: previous studies have shown that these groups have almost no diabetes and cardiovascular problems. However, there are many examples with Tsimane people developing Type II Diabetes and other health issues after moving to neighboring villages and taking up sedentary jobs.

Here’s where things get really interesting: the calorie intake of people like the Tsimane and the Hadza is comparable to that of the average American. However, they have excellent fitness, extremely low rates of obesity and cancer, and are generally free from any chronic diseases. The reasons for this may not be all that jolly, however.

Infant mortality rates are high, and fatalities from infections and accidents are extremely high. Those who do manage to reach adulthood are more likely to be very healthy. They are active until old age, walking at least 5-10 miles a day, and exhibit very alert and active lifestyles. While calorie-wise this doesn’t make as much of a difference as you might expect, it does wonders for your health.

However, considering that when these people give up their native lifestyles they start to develop disease rates comparable to industrialized countries, the key seems to be in their lifestyle, not their diets. It is possible that genetics and other factors unrelated to lifestyle help protect them from chronic diseases — but there’s still another factor to consider.

Choice and variety

Foods rich in fibers are a staple of a healthy diet. This was one of the very few similarities across all investigated diets. Image credits: Keith Weller, USDA.

Another big difference between peoples like the Hadza and the Tsimane and modern urban people is the amount of variety in the diet. We pretty much take it for granted nowadays, but we have access to an unprecedented culinary variety. For all the obvious advantages that come with this, there’s also a disadvantage: it can make us overeat.

It’s called sensory-specific satiety, and it means that the more you eat a type of food, the less satisfaction you derive decreases in time. As a consequence, your appetite decreases when you keep eating the same type of food and increases when you keep eating different things — that’s why you always have room for dessert after a savoury meal. In truth, however, you don’t have the extra room, and you’re probably overeating.

The bottom line is that we’re not really sure what diets work best, but there seem to be some generally applicable rules: eat fiber-rich foods like fruits and veggies, avoid energy-dense foods (like sweets or meats), and keep an active lifestyle.

“A more integrative understanding of hunter‐gatherer health and lifestyle, including elements beyond diet and activity, will improve public health efforts in industrialized populations,” researchers conclude.

The study “Hunter‐gatherers as models in public health” by Pontzer, Wood, and Raichlen, has been published in Obesity Reviews.