Examining the Nutritional Quality and Environmental Impact of Popular Diets

A new study published in The American Journal of Clinical Nutrition has looked at the nutritional quality and environmental impact of popular contemporary diets, such as the keto, paleo, vegan, or omnivorous diets. The researchers, led by Professor Diego Rose of Tulane University, used data from more than 16,000 adult meals collected by the Centers for Disease Control and Prevention (CDC) to create diet quality ratings.^[0]

After the analysis was conducted, it was discovered that the keto and paleo diets had some of the lowest scores in terms of overall nutrition quality. Furthermore, these two diets had the highest carbon emissions at 3kg and 2.6kg of CO2 per 1,000 calories consumed respectively. The keto diet involves a high intake of fats and low intake of carbs, while the paleo diet excludes beans and grains in favor of meats, nuts, and vegetables.

In contrast, a vegan diet had the least environmental impact, and a pescatarian diet was the most nutritionally beneficial.^[1] The researchers noted that when those on omnivorous diets opted for plant-forward diets such as the Mediterranean or meat-limiting DASH diets, both carbon footprints and nutritional quality scores improved.^[2]

A 2021 United Nations-backed study found that 34 percent of greenhouse gas emissions come from the food system, with beef production being responsible for eight to ten times more emissions than chicken production and over 20 times more emissions than nut and legume production.^[0]

Professor Rose said that while scientists have looked at the nutritional impact of keto and paleo diets, this is the first time researchers have quantified the carbon footprints of each diet and compared them to other popular diets.

In the future, Rose is still uncertain about how to promote dietary patterns which are healthier for both people and the environment.^[3] What impacts might different policies have on results and how could those help us transition to more nutritious, greener diets?^[4] Rose^[5] Our findings suggest that taking this course of action would be beneficial for both your ecological impact and overall wellbeing. Our research reveals that there is a way to increase one's health and reduce their environmental impact without having to completely give up meat.

0. “Study reveals the environmental impacts of various diets” Earth.com, 1 Mar. 2023, https://www.earth.com/news/study-reveals-the-environmental-impacts-of-various-diets/

1. “Bad News, Keto Dieters – It's Less Healthy And Sustainable Than Going Vegan” IFLScience, 1 Mar. 2023, https://www.iflscience.com/bad-news-keto-dieters-it-s-less-healthy-and-sustainable-than-going-vegan-67758

2. “Keto, paleo, vegan: Which diet does the most to cut your carbon footprint?” Euronews, 2 Mar. 2023, https://www.euronews.com/green/2023/03/02/keto-paleo-vegan-which-diet-does-the-most-to-cut-your-carbon-footprint

3. “Two diets have highest emissions, lowest quality” Futurity: Research News, 2 Mar. 2023, https://www.futurity.org/diets-most-emissions-2882902/

4. “These 2 diets followed by top celebrities are actually the worst for you — and the environment!” Study Finds, 1 Mar. 2023, https://studyfinds.org/keto-paleo-diets-the-worst/

5. “Keto and paleo diets branded “least sustainable” in study” New Food, 2 Mar. 2023, https://www.newfoodmagazine.com/news/190176/keto-and-paleo-diets-branded-least-sustainable-in-study