Tag Archives: carbs

Credit: Pixabay.

Low-carb diets are unsafe and should be avoided

Credit: Pixabay.

Credit: Pixabay.

Diets that focus on consuming as few carbohydrates as possible are popular — they might also be extremely harmful. According to a recent study, individuals who were on a low-carb diet had a greater risk of premature death, particularly due to coronary heart disease, stroke, and cancer. The authors conclude that “these diets should be avoided.”

The study examined the relationship between low carbohydrate diets and all-cause death in a nationally representative sample of 24,825 participants of the US National Health and Nutrition Examination Survey (NHANES) from 1999 to 2010.

The participants were at an average of 47.6 years of age and almost equally represented men and women. The international team of researchers divided them into quartiles based on the proportion of carbohydrates present in their diets. Risks of death from coronary heart disease, cerebrovascular disease, and cancer were increased by 51%, 50%, and 35%, respectively. The link was strongest in non-obese, older participants, researchers reported today at the European Society of Cardiology Congress 2018. 

Carbohydrates include foods such as fruit, vegetables, and sugar, but most often people ingest the most carbs from starchy foods such as potatoes, rice, and pasta. Low-carb diets are touted as being highly effective for weight loss. However, studies such as this suggest that, in the long run, low-carb diets can be dangerous.

Forest plot of low carbohydrate diets and risk of total mortality. Credit: European Society of Cardiology.

Forest plot of low carbohydrate diets and risk of total mortality. Credit: European Society of Cardiology.

But that’s not to say that people should eat a lot of carbs. Finding that sweet spot is challenging work, which Maciej Banach, a Professor at the Medical University of Lodz, Poland, and one of the lead authors of the study, is trying to answer. He and colleagues wanted to answer exactly what level of carbohydrates, expressed in grams, in every-diet might be considered dangerous. They were not able to answer this directly due to the way carb intake is being evaluated nowadays using the Willett method, which expresses a percentage of energy from a given nutrient.

The authors also plan on investigating when a low-carb diet stops offering dividends and starts to negatively affect health. In the short-term, low-carb dieting not only leads to weight loss but also lowers blood pressure and improves blood glucose control.

“Now we have been working to give direct answer on the number of calories and/or grams of carbohydrates per day that might be acceptable in our diet. But we believe that for carbohydrates it is a kind of U-curve, so for sure we should avoid too much carbohydrates in our diet, but, based on our results, it is also not recommended to use restricted low carbohydrates diet, especially for the long-time,” Banach told ZME Science.

Another study recently, published in The Lancet, which followed 15,428 American adults aged 45-64 years from 1987 until 2012, found that low-carb diets were associated with reduced lifespan. The findings were confirmed by a meta-analysis of data from eight prospective cohorts involving 432,179 people in North American, European, and Asian countries.

“It is usually recommended to use a healthy, well-balanced diet in order to lose weight max. 1 kg per week (usually about 1000 calories per day). There are many well-known and very healthy diets, with great scientific evidence, including Mediterranean or DASH diets,” Banach said.

 

Low-carb diets may be cutting years off your life, new study says

A lot of people looking to lose weight are trying low-carb diets such as Keto or Atkins, but in doing so they may be shaving years off their lifespan. According to a 25-year-long study, individuals whose diets were either low or high in carbohydrates had a higher risk of death than those who consumed a moderate amount of carbs. Another important finding was that switching meat for plant-based protein led to healthier outcomes, in people with low-carb diets.

Pasta is a high-carb dish. Credit: Pixabay.

For their study, researchers followed 15,428 American adults aged 45-64 years from 1987 until 2012. The participants had to self-report their diets, based on which the researchers estimated the proportion of calories they got from carbohydrates, fats, and protein.

After correlating health outcomes with diet, researchers found that, over a 25-year period, people who had a moderate carbohydrate intake (50-55% of daily calories) had an average life expectancy of 83 years — that’s four years longer than those with low carb intake (40%), who lived only 79 years on average. Participants with a high carb intake (more than 70% of daily calories) had an average life expectancy of 82 years, slightly lower than the moderate carbs intake group.

Carbohydrates include foods such as fruit, vegetables, and sugar but most often people ingest the most carbs from starchy foods such as potatoes, rice, and pasta.

The researchers at the Brigham and Women’s Hospital, Boston, then compared low-carb diets rich in animal protein and fats with those that contained lots of plant-based protein and fat. They found that the latter diet slightly reduced the risk of death.

Low-carb diets that replace carbohydrates with protein or fat are becoming increasingly popular. The new study published in The Lancet, however, suggests that people ought to be more careful and shouldn’t jump on the latest diet fad before doing proper research.

Although previous randomized trials have shown low carbohydrate diets are beneficial for short-term weight loss and improve cardiometabolic risk, this study shows that low-carb dieting may shorten lifespan if done for many years.

“We need to look really carefully at what are the healthy compounds in diets that provide protection”, says Dr. Sara Seidelmann, Clinical and Research Fellow in Cardiovascular Medicine from Brigham and Women’s Hospital, Boston, USA who led the research.

“Our data suggests that animal-based low carbohydrate diets, which are prevalent in North America and Europe, might be associated with shorter overall lifespan and should be discouraged. Instead, if one chooses to follow a low carbohydrate diet, then exchanging carbohydrates for more plant-based fats and proteins might actually promote healthy aging in the long term.”

In the same study, the authors also performed a meta-analysis of data from eight prospective cohorts involving 432,179 people in North American, European, and Asian countries. The analysis revealed similar trends — participants whose diet consisted of high and low in carbohydrates had shorter life expectancy than those with moderate consumption.

“These findings bring together several strands that have been controversial. Too much and too little carbohydrate can be harmful but what counts most is the type of fat, protein, and carbohydrate,” says Walter Willett, Professor of Epidemiology and Nutrition at Harvard T. H. Chan School of Public Health and co-author of the study.

As a caveat, there are some limitations to this study. The conclusions are associations not causal relationships and the researchers had to rely on the participants to remember what they had eaten in order to determine their diets. The food questionnaire in the study may have also led some people to underestimate the calories and fat they had eaten. More research will likely follow but, in the meantime, it may be a good idea to stay away from low-carb diets.

 

donut

Why we can’t resist donuts — our brain is wired to love fats and carbs together

donut

Credit: Pixabay.

Humans have a soft spot for carbs or fats. But boy, oh boy, do our brains go haywire when you combine the two. According to a recent study, people are willing to pay more for foods high in both, such as donuts or Doritos, than for products rich in only one of the two. After delving deeper, the researchers found that our brains flare-up in craving centers when we’re presented with the magic combination.

“Our study shows that when the signals are combined they make foods more reinforcing,” said Dana Small, professor of psychiatry at Yale and senior author of the paper, in a statement.

The research team at Yale University recruited 56 hungry volunteers and scanned their brains as they were shown pictures of various foodstuffs high in fat, high in carbohydrates, or high in both. The participants were Caucasian, roughly equally distributed among males and females, had an average age of 25 and an average BMI of 22.6 (normal weight).

After the brain scanning, each participant was asked to bid cash in an auction for the kind of food they wanted to snack on. The stimuli were chosen to depict equi-caloric portions, be similarly liked, and familiar. For instance, cheese for fat, pretzels for carbs, pastries for both.

As predicted, the participants are willing to pay more for snacks with fat and carbohydrate, compared with fat or carbohydrate alone. What’s more, the amount they’d pay for the combination foods was more than you would predict by summing the prices for fats and carbs separately.

Examples of each macronutrient group are displayed in (A). . A picture of a food item to be bid on was displayed for 5 s. Participants then had 5 s to make a bid on the item. They moved a trackball inside the scanner to move a cursor back and forth between 0 and 5 euros. After they submitted their response it remained on screen for the remainder of the 5 s. Credit: Cell Metabolism.

Examples of each macronutrient group are displayed in (A). . A picture of a food item to be bid on was displayed for 5 s. Participants then had 5 s to make a bid on the item. They moved a trackball inside the scanner to move a cursor back and forth between 0 and 5 euros. After they submitted their response it remained on screen for the remainder of the 5 s. Credit: Cell Metabolism.

When the researchers took a look at the brain scans, they found that activity in two brain areas in particular, the caudate and putamen, was much stronger in response to both fats and carbs together than either one alone. These brain areas are associated with craving, reward, and goal-oriented actions, and release dopamine when a person encounters an exciting stimulus.

In the modern food environment that is rife with processed foods high in fat and carbohydrate like donuts, French fries, chocolate bars, and potato chips, this reward potentiation may backfire to promote overeating and obesity,” Small said.

Foods that are high in both fat and carbs do not exist in nature, with one single exception: breast milk. Fruits are high in sugar, but not in fat, and meat is high in fat but not high in carbs. So modern food is hijacking the neural systems that evolved in the course of thousands of years — no wonder obesity is such a problem in the developed world.

Knowing that the human brain is vulnerable to such stimuli should encourage people to pay particular attention to this class of foods in order to avoid becoming overweight or obese. Bear in mind that junk food companies have known this intuitively for a long time, and directly market to our cravings.

The findings appeared in the journal Cell Metabolism.