WASHINGTON, DC—A vegan diet improves diet quality, leading to weight loss 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. Decreased weight was most associated with increased consumption of legumes and reduced consumption 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 food you eat,” says Hana Kahleova, MD, PhD, director of clinical research at the Physicians Committee and co-author of the study. “That means avoiding animal products and following a vegan diet rich in fruits, vegetables, grains and beans.”
Participants in the 16-week study included 244 overweight adults who were randomly assigned to make no diet changes or to follow a low-fat, calorie-restricted vegan diet consisting of vegetables, grains, legumes and fruit. The researchers tracked 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 records.
Participants on the vegan diet lost an average of 13 pounds and 9.1 pounds of body fat. Body weight and fat mass did not decrease in the group that made no diet changes. In the vegan group, increased consumption of fruits, legumes, meat alternatives and whole grains and decreased consumption of animal products, added oils and animal fats were associated with weight loss:
- Fruit: Increased consumption of whole fruits was associated with decreased body weight.
- Legumes and Meat Alternatives: Increased pulse consumption was associated with decreased weight, fat mass, and visceral adipose tissue. Consuming more meat alternatives, including tofu, tempeh, and veggie burgers, was associated with lower body weight.
- Cereals: Increased consumption of whole grains was associated with decreased body weight and fat mass.
- Eggs and dairy products: A decrease in egg consumption was correlated with a decrease in weight. A decrease in the consumption of high-fat dairy products was associated with a decrease in body weight and fat mass.
- Meat, fish and poultry: Reductions in the combined intake of meat, fish and poultry have been associated with weight loss and decreased fat mass.
- Added fats: Decreased intake of added animal fats was associated with decreased body weight and fat mass. Decreased intake of added oils was also correlated with decreased weight and fat mass.
The vegan group also experienced improvements in insulin sensitivity.
The vegan group’s diet quality, as measured by the Alternative Healthy Eating Index-2010 (AHEI) score, also increased by an average of 6 points, in contrast to no significant change in the group that did not change their diet. The AHEI was developed by researchers at the Harvard School of Public Health to identify dietary habits associated with a lower risk of chronic disease. The index is made up of which foods to eat more often, such as fruits and vegetables, and which to eat less often, such as red meat and processed meat. The higher the AHEI score, the lower the risk of chronic disease.