Vegan diet rich in legumes beneficial for weight loss in new study

WASHINGTON, DC — A vegan diet improves diet quality, leading to lower weight and improved insulin sensitivity, according to a new study by the Physicians Committee for Responsible Medicine, published in the Journal of the Academy of Nutrition and Dietetics. Weight loss was most associated with increased intake of legumes and decreased intake of meat, fish and poultry.

“Our research shows that the best way to improve the quality of your health is to improve the quality of the foods you eat,” said Hana Kahleova, MD, PhD, director of clinical research at the Physicians Committee and a co – author of the study. “That means avoiding animal products and eating a vegan diet rich in fruits, vegetables, grains and beans.”

The participants in the 16-week study included 244 overweight adults who were randomly assigned to either make no dietary changes or follow a low-fat vegan diet, with no calorie restrictions, consisting of vegetables, grains, legumes and fruits. Researchers monitored diet quality, body weight, fat mass and insulin sensitivity. The final data analysis included 219 participants who completed the entire study and submitted their final dietary data.

Participants on the vegan diet lost an average of 13 pounds and 9.1 pounds of fat mass. Body weight and fat mass did not decrease in the group that made no dietary changes. In the vegan group, increases in fruit, legumes, meat alternative and whole grain intakes and decreases in animal products, added oils and animal fats were associated with weight loss:

• Fruit: An increased intake of whole fruit was associated with a decrease in body weight.
• Legumes and meat alternatives: Increased consumption of legumes was associated with decreased weight, fat mass and visceral adipose tissue. Consuming more meat alternatives, including tofu, tempeh and veggie burgers, was associated with a decrease in body weight.
• Grains: Increased consumption of whole grains was associated with decreased body weight and fat mass.
• Eggs and dairy products: Reduced egg intake was correlated with reduced weight. Reduced high-fat dairy intake was associated with reduced weight and fat mass.
• Meat, fish and poultry: Reducing the combined intake of meat, fish and poultry was associated with weight loss and a decrease in fat mass.
• Added fats: Decreases in the intake of added animal fats were associated with a decrease in weight and fat mass. A reduced intake of added oils also correlated with a decrease in weight and fat mass.

The vegan group also experienced improvements in insulin sensitivity.

The nutritional quality of the vegan group, as measured by the Alternative Healthy Eating Index-2010 (AHEI) score, also increased on average by 6 points, as opposed to no significant change in the no-diet group. The AHEI was developed by researchers at the Harvard School of Public Health to identify dietary patterns associated with a lower risk of chronic disease. The index consists of foods that are eaten more often, such as fruits and vegetables, and foods that are eaten less frequently, such as red and processed meat. The higher the AHEI score, the lower the risk of chronic disease.

Founded in 1985, the Physicians Committee for Responsible Medicine is a nonprofit organization that promotes preventive medicine, conducts clinical research, and encourages higher standards of ethics and effectiveness in teaching and research.