Tag Archives: plant based diet

Your mouth can help stop climate change — if it eats less meat

Eliminating the use of animals as food would substantially reduce our emissions of greenhouse gas emissions and give us a fighting chance against the climate crisis, a new study. Researchers called for a massive switch to a plant-based diet, as the replacement of fossil fuels for renewables won’t be enough to meet climate goals.  

Image credit: Flickr / Steven Penton.

The Food and Agriculture Organization (FAO) of the United Nations that animal agriculture accounts for 14.5% of all emissions, but this is almost certainly an underestimate. Animal agriculture accounts for an oversized part of our total agricultural emissions, and research is increasingly showing that reducing our consumption of animal products (especially red meat) could make a real difference.

A large part of the emissions impact of animal agriculture comes from methane (CH4) and nitrous oxide (N2O), which are more potent than CO2 but decay more rapidly. While these emissions can be reduced by increasing efficiency and yields, for example, this won’t have the same impact as a transition to a plant-rich diet, the researchers argue. 

“We wanted to answer a very simple question: What would be the impact of a global phase-out of animal agriculture on atmospheric greenhouse gases and their global-heating impact?” Patrick Brown, founder and CEO of Impossible Foods and a professor emeritus at Stanford University, who co-authored the paper, said in a statement.

Turning away from beef 

Brown and Michael Eisen, a professor of genetics at UC Berkeley, used publicly available data on livestock production, livestock-linked emissions, and biomass recovery potential on land currently used to support livestock to predict how the phaseout of all or parts of global animal agriculture production would alter net anthropogenic emissions. 

They then used a simple climate model to project how these changes would impact the evolution of atmospheric GHG levels and warming for the rest of the century. They calculated the combined impact of reduced emissions and biomass recovery by comparing the reduction of emissions under different livestock replacement scenarios. 

The two researchers looked at four specific dietary scenarios: replacing all animal agriculture now with a plant-based diet, a more gradual one, a more realistic one, with a 15-year transition to plant-based diets, and forms of each to replace beef with plant-based products. For each, they assumed that non-agriculture emissions would remain high.

Based on their climate model, the researchers estimated that phasing out animal agriculture over the next 15 years would cut 68% of CO2 emissions by 2100. This would provide 52% of the emission-reduction necessary to limit global warming to 2 degrees Celsius, the goal included in the Paris Agreement on climate change signed by every country. 

“The combined effect is both astoundingly large, and – equally important – fast, with much of the benefit realized by 2050,” Brown said in a statement. “If animal agriculture were phased out over 15 years and all other greenhouse-gas emissions were to continue unabated, the phase-out would create a 30-year pause in net emissions.”

Still, Brown and Eisen acknowledge that the transition away from animal agriculture will face many obstacles and create many additional challenges. Meat, dairy, and eggs are a major component of global human diets, and the raising of livestock is integral to rural economies, with over a billion people making their living from animal agriculture.

The substantial global investment will be required to ensure that the people who currently make a living from animal agriculture do not suffer when it is reduced or replaced. Policymakers will also have to pursue investment to prevent food insecurity in regions where wide access to a diverse and healthy plant-based diet is currently lacking. 

Although animal products currently provide, according to the recent FAO data, 18% of the calories, 40% of the protein, and 45% of the fat in the human food supply, they are not necessary to feed the global population, they argue. Existing crops could replace the calories, protein, and fat from animals with a vastly reduced environmental impact. 

“We have shown that global dietary change provides a powerful complement to the indispensable transition from fossil fuels to renewable energy systems. The challenge we face is not choosing which to pursue, but rather in determining how best to overcome the many social, economic and political challenges to implement both,” the researchers wrote. 

It’s fair to say that Brown, as the founder of Impossible Foods, would likely benefit economically from the reduction of animal agriculture. Nevertheless, the findings of his study are based on academic research and are in line with many previous studies that have highlighted over the years the climate footprint of the food sector overall and the need to address it.

The study was published in the journal PLOS Climate

Not all plant-based diets are the same when it comes to heart health

Plant based diets are often recommended to reduce the risk of health disease, but things might not be so straightforward, a new study reports.

Image via Pixabay.

Just so we get this out of the way: a plant based diet doesn’t mean you’re a vegetarian. The use of the phrase has changed over time and may still vary depending on context — people might associate it with vegetarianism or even veganism, but in this context, it does what it says on the label: it’s a diet mostly based on plants, featuring low intake of animal products.

“We specifically studied diets that were higher in intake of plant foods, and lower in intake of animal foods. The diets we studied were not vegan or vegetarian diets in which some or all animal foods are completely excluded. Hence, this study cannot address the question of coronary heart disease risk associated with not eating meat or other animal foods at all,” lead author Ambika Satija, a postdoctoral fellow at the Harvard T.H. Chan School of Public Health in Boston clarified for ZME Science.

In this sense, over 4 billion people live primarily on a plant-based diet, and that’s actually very good news for the environment, as eating meat is dramatically unsustainable, but that’s a story for a different time. Satija and her colleagues found that shifting to a plant based diet does reduce the risk of cardiovascular diseases — but only if you eat the right things.

People who ate vegetables, beans, and whole grains did, in fact, enjoy a significantly lower risk of coronary heart disease. But people who were on a less healthy — but still plant based — diet didn’t fare better. Actually, diets heavy in pasta, bread, potatoes, and sweets were just as bad or worse than their counterparts with more animal products. In other words, not all plant-based diets are the same.

In total, she analyzed 166,000 women and 43,259 men, based on three studies that began in the 1980s and 1990s. The participants responded to a follow-up questionnaire every two years for over two decades on lifestyle, health behaviors, and medical history. Participants with underlying conditions were excluded from the study.

Overall, plant based diets did reduce the coronary risk disease. However, previous studies just draw the final line, failing to consider the differences between different types of plant diets.

Ambika Satija showed that it’s not all about eating plants — it matters a lot what plants you eat. Image credits: Harvard T Chan.

“When we examined the associations of the three food categories with heart disease risk, we found that healthy plant foods were associated with lower risk, whereas less healthy plant foods and animal foods were associated with higher risk,” said Satija. “It’s apparent that there is a wide variation in the nutritional quality of plant foods, making it crucial to take into consideration the quality of foods in a plant-based diet.”

Satija also added that instead of thinking in terms such as “vegetarian” or “plant based,” it’s important to consider the quality of the food. Eating plants doesn’t necessarily make you healthier, but eating the right one certainly does.

“It is important to think in terms of the quality of plant foods consumed in the diet (whether we call the diet “plant-based” or “vegetarian”), with a focus on higher quality plant foods, such as whole grains, nuts, legumes, fruits, vegetables, etc.”

Journal Reference: Ambika Satija, Shilpa N. Bhupathiraju, Donna Spiegelman, Stephanie E. Chiuve, JoAnn E. Manson, Walter Willett, Kathryn M. Rexrode, Eric B. Rimm, Frank B. Hu — Healthful and Unhealthful Plant-Based Diets and the Risk of Coronary Heart Disease in U.S. AdultsDOI: 10.1016/j.jacc.2017.05.047