Swapping Meat and Dairy for Plant‑Based Foods Cuts Climate Pollution by 35%, Randomized Clinical Trial Shows

WASHINGTON, D.C. — A simple change on the dinner plate could deliver a powerful climate impact. New research published in BMJ Nutrition, Prevention & Health shows that replacing meat and dairy with a low‑fat vegan diet that includes soybeans reduced diet‑related greenhouse gas emissions by 35%. For the average individual, that reduction is comparable to eliminating roughly 600 miles of driving each year.

“If you’re looking for a powerful way to shrink your carbon footprint, start with what’s on your plate,” says Hana Kahleova, MD, PhD, director of clinical research at the Physicians Committee for Responsible Medicine and the lead author of the new research. “Making this swap can help you reduce your greenhouse gas emissions as much as eliminating 600 miles of driving.”

The study analyzed dietary records from a randomized clinical trial of postmenopausal women who adopted a low‑fat vegan diet with half a cup of soybeans daily for 12 weeks. Researchers linked participants’ food intake to environmental impact databases to estimate greenhouse gas emissions and energy demand associated with their diets.

The results were striking:

• Greenhouse gas emissions dropped by 35%.
• Total energy required to produce participants’ food fell by 34%.
• The reductions were driven largely by eliminating meat and dairy products.

The dietary intervention also produced major health improvements. In the original clinical trial, participants experienced a 92% reduction in severe hot flashes and lost an average of about 8 pounds.

The researchers found that GHGE decreased in the vegan group by 35% (662.7 g CO2-eq/person day), compared with no change in the control group. This decrease was mainly attributable to reduced meat and dairy consumption. Per person, the reduction is equivalent to eliminating approximately 600 miles. The reduction in GHGE also correlated with a reduction in severe hot flashes for the women in the study.

Cumulative energy demand (CED), which estimates total energy used to produce, process, package, transport, store, and dispose of the waste of food, decreased in the vegan group by 34% (-4956 kJ/person day), compared with no change in the control group. The decrease was also mainly attributable to reduced meat and dairy consumption. The reduction in CED is equivalent to the electricity required to power an average U.S. household for roughly two hours.

“This research shows that replacing meat and dairy with plant‑based foods can dramatically cut emissions while improving health at the same time,” says Dr. Kahleova.

Physicians Committee research published in JAMA Network Open last year also showed the benefits of a vegan diet for reducing GHGE and CED.

“Dietary choices are one of the most immediate actions individuals can take to reduce climate pollution,” Dr. Kahleova added. “Even modest changes, when adopted widely, could have a meaningful impact on climate change.”

Food production is a major contributor to climate change, and diets high in animal products generate substantially more greenhouse gases than plant‑based diets. Researchers say widespread dietary shifts toward plant‑based foods could play a key role in reducing the environmental footprint of the global food system. A recent survey found that nearly half of Americans would consider eating a plant-based diet to help reduce greenhouse gas emissions.