The paleo diet is based on the idea that modern foods — such as grains, dairy and legumes — don’t match our genes. This mismatch is thought to be behind chronic diseases like obesity, diabetes and heart disease.
Paleo dieters are encouraged to eat plenty of fresh fruit and vegetables, as well as high-quality protein. They also avoid grain products and saturated fats, such as ghee and lard.
Following a keto or paleo diet is associated with “negative climate impacts”, latest evidence indicates.
Research conducted by academics from Tulane University in America has found that keto and paleo diets produce the most carbon emissions and are the least nutritious.
For every 1,000 calories consumed on the keto diet, nearly 3kg of carbon dioxide is produced, the results have revealed.
A keto diet is a very low, low carb diet of less than 30g of carbohydrates a day.
Meanwhile, a paleo diet generates 2.6 kg of carbon dioxide for every 1,000 calories consumed, the research has reported.
A paleo diet is a modern diet that consists of foods considered to be similar to those consumed by humans during the Paleolithic period.
According to the findings, a vegan diet is the most sustainable meal plan, generating 0.7 kg of carbon dioxide per 1,000 calories consumed.
Following a vegetarian meal plan was also found to be sustainable and a pescatarian diet scored the highest on nutritional quality, the scientists have said.
More than 16,000 people’s diets were examined during the study. Each participant was scored on how nutritious and carbon effective their diet is.
Chief author Professor Diego Rose said: “While researchers have examined the nutritional impact of keto and paleo diets, this is the first study to measure the carbon footprints of each diet, as consumed by U.S. adults, and compare them to other common diets.
“We suspected the negative climate impacts because they’re meat-centric, but 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.”
Approximately 86% of the participants followed an omnivore diet, which finished in the middle of the rankings for its nutritious quality and sustainability.
Experts have said if 30% of meat eaters started following a vegetarian diet, the effect would be similar to removing 340 million passenger vehicle miles.
Professor Rose added: “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.
“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.”
A previous study has reported that more than 30% of greenhouse gas emissions are generated from the food system.
This research shows that beef production generates 20 times more emissions than the production of nuts and up to 10 times more emissions than chicken production.
Professor Rose added: “I think the next question is how would different policies affect outcomes and how could those move us toward healthier, more environmentally friendly diets.”
The study was published in The American Journal of Clinical Nutrition.