A global transition to a vegetarian diet would have significant impacts in the battle against global warming and other environmental concerns, according to research conducted at Loma Linda University Health.
Food production has been identified as a major contributor to increased greenhouse gas emissions, consumes 70% of fresh water, and is responsible for 80% of the world’s deforestation. Improving agricultural technology and reducing food waste have been put forward as potential solutions to these environmental concerns. But Joan Sabaté MD, DrPH, professor of nutrition and epidemiology at Loma Linda University School of Public Health, found that changes in food choices and diet patterns would have a far greater positive effect on environmental sustainability.
Vegetarian Diets: Planetary Health and Its Alignment with Human Health is a meta-analysis of 49 published research studies that focused on the impact that vegetarian and vegan diets have on greenhouse gas emissions, and water and land use. When the data from the 49 studies was combined, Sabaté found that shifting from current dietary norms to ovolactovegetarian and vegan diets would reduce greenhouse gas levels an average of 35%, reduce land usage for food production by an average of 42%, and agricultural water usage by an average of 28%.
“Many other studies have clearly demonstrated the health advantages of vegetarian and vegan diets. This analysis confirms that switching to these types of diets are also significantly eco-friendly as well,” Sabaté said.
Sabaté directs the environmental nutrition research program at Loma Linda University School of Public Health. This program explores the interrelationships between the environmental and health impacts of food choices, and ultimately seeks to improve the sustainability, health and equity of food systems. He is the editor of the book Environmental Nutrition: Connecting Health and Nutrition with Environmentally Sustainable Diets, published in 2019.
One early sign that people are increasing in their commitment to make dietary changes due to concerns about climate took place in earlier this year. By choosing to serve all vegan meals to hundreds of celebrities and guests, two major entertainment industry award shows — the Golden Globe Awards and the Screen Actors Guild Awards — increased public awareness and conversation about the link between sustainable agriculture and climate change.
While Sabaté says the field of sustainable diet and environmental impacts is still in its infancy, he has participated in a number of research studies that show clear connection between diet and climate factors. In 2017, he was part of a group that published a well-known study on the climate benefits of replacing meat in diets with beans. Sabaté and other researchers working in Loma Linda University Health’s environmental nutrition program have published more than 30 papers that examined the relationship between food choices, environmental sustainability and population health.
Sabaté says additional research is needed into how changes in agricultural approaches impact the environment in low- and middle-income countries. He also points to needed research comparing large-scale agricultural operations with small-operation family farms practices.
“In societies where daily meat consumption is the social norm, drastically reducing meat consumption is a major challenge," Sabaté said. “In low- and middle-income countries, eliminating meat could adversely affect those populations’ already marginal nutritional status.
The paper was presented at the 7th International Congress on Vegetarian Nutrition in 2018, the premiere scientific conference on plant-based diets, which occurs every five years. The proceedings from the conference were recently published in a special edition of the journal Advances in Nutrition.