Two randomized clinical trials led by Hana Kahleova, MD, PhD, director of clinical research at the Physicians Committee for Responsible Medicine, found that a low-fat vegan diet reduces diet-related greenhouse gas emissions by over half. The trials showed that participants following a vegan diet experienced improvements in metabolic health that surpassed those on portion-controlled omnivore and Mediterranean diets.

The studies, published in Current Developments in Nutrition and BMJ Nutrition, Prevention & Health, used actual dietary intake data from randomized trials rather than projections, reinforcing the reliability of the findings. Participants on the vegan diet saw reductions in insulin requirements, improved insulin sensitivity, weight loss, and lower cholesterol levels. The environmental gains were attributed to the removal of meat and dairy, which are considered the most resource-intensive components of diets, highlighting the impact of dietary choices on both individual health outcomes and environmental sustainability.