Insights from the Latest Study: A Comprehensive Analysis of Six Popular Diets Reveals the Truth About Keto and Paleo Diets.

A new study from Tulane University compared popular diets based on their nutritional quality and how they affect the environment. The keto and paleo diets, as they are eaten by American adults, scored among the lowest for overall nutritional quality and were among the highest for carbon emissions.

The keto diet, which focuses on eating lots of fat and few carbs, was believed to produce almost 3 kg of carbon dioxide for every 1,000 calories eaten.

The paleo diet, which doesn’t eat grains or beans but instead focuses on meats, nuts, and vegetables, got the next-to-worst score for quality and produced 2.6 kg of carbon dioxide per 1,000 calories, which is a lot.

Data from more than 16,000 adult meals gathered by the CDC’s National Health and Nutrition Examination Survey were used to create diet quality ratings for the research, which was published in The American Journal of Clinical Nutrition.

The federal Healthy Eating Index was used to give point values to certain diets, and average scores for those following each kind of diet were determined.

According to the senior author of the study, Diego Rose, who is a professor and nutrition program director at Tulane University School of Public Health and Tropical Medicine, previous research has explored the nutritional effects of keto and paleo diets. However, the latest study is unique in that it analyzes the carbon footprints of these diets as consumed by adults in the United States and compares them to those of other commonly followed diets.

“We suspected the negative climate impacts because they’re meat-centric, but,” adds Rose, “no one had really compared all these diets – as they are chosen by individuals, instead of prescribed by experts – to each other using a common framework.”

A vegan diet, on the other hand, was shown to have the least detrimental effect on the environment, producing just 0.7 kg of carbon dioxide per 1,000 calories ingested. This is less than a fourth of the impact that the keto diet has on the environment. The vegan diet was the most influential, followed by vegetarian and then pescatarian diets.

Among the diets examined, the pescatarian diet had the best nutritional quality, with the vegetarian and vegan diets coming in second.

The omnivore diet, which was chosen by 86% of the people who took the survey, was in the middle of the pack in terms of both quality and sustainability.

According to the research, 340 million passenger car miles would be saved if a third of those who now consume omnivore diets switched to vegetarian on a daily basis.

Significantly, however, both carbon footprints and nutritional quality ratings improved whether omnivores chose the plant-forward Mediterranean or the fatty meat-restricting DASH diet variations.

“Climate change is arguably one of the most pressing problems of our time, and a lot of people are interested in moving to a plant- based diet,” explains Rose. “Based on our results, that would reduce your footprint and be generally healthy. Our research also shows there’s a way to improve your health and footprint without giving up meat entirely.”

According to a research funded by the United Nations in 2021, the food system is responsible for 34% of greenhouse gas emissions.

Food production accounts for the majority of those emissions, with beef producing 8–10 times more emissions than chicken and more than 20 times more emissions than nut and legume cultivation.

Even though many studies have been done on how certain foods affect the environment, Rose said that this study was important because “it considers how individuals select popular diets that are composed of a wide variety of foods.”

Rose still doesn’t know how to get people to eat in ways that are good for both people and the planet.

“I think the next question is how would different policies affect outcomes and how could those move us toward healthier, more environmentally friendly diets?” Rose adds.

Source: 10.1016/j.ajcnut.2023.01.009

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