Vegan diet better for weight loss, cholesterol control than Mediterranean diet

A low-fat vegan diet has better outcomes for weight, body composition, insulin sensitivity, and cholesterol levels compared to a Mediterranean diet, according to a new randomized crossover trial that compared the diets head-to-head, which was published in the Journal of the American College of Nutrition.

For the study, researchers randomly assigned participants who were overweight and had no history of diabetes to a vegan diet or a Mediterranean diet. For 16 weeks, half of the participants started with a low-fat vegan diet that eliminated animal products and focused on fruits, vegetables, whole grains, and legumes. The other half started with the Mediterranean diet, which followed the PREDIMED protocol, which focuses on fruits, vegetables, legumes, fish, low-fat dairy, and extra virgin olive oil, while limiting or avoiding red meat and saturated fats.

Neither group had a calorie limit, and participants did not change exercise or medication routines, unless directed by their personal doctors. As part of the crossover design, participants then went back to their baseline diets for a four-week washout period before switching to the opposite group for an additional 16 weeks.

The study found that within 16 weeks on each diet participants lost an average of about 13 pounds on the vegan diet, compared with no mean change on the Mediterranean diet. Additionally, participants lost about 7.5 pounds more fat mass and saw a greater reduction in visceral fat on the vegan diet.

The vegan diet decreased total and LDL cholesterol levels by 18.7 mg/dL and 15.3 mg/dL, respectively, while there were no significant cholesterol changes on the Mediterranean diet. Blood pressure decreased on both diets, but more on the Mediterranean diet at 6.0 mmHg, compared to 3.2 mmHg on the vegan diet, according to the study.

The authors note that the vegan diet likely led to weight loss because it was associated with a reduction in calorie intake, increase in fiber intake, decrease in fat consumption, and decrease in saturated fat consumption.

"While many people think of the Mediterranean diet as one of the best ways to lose weight, the diet actually crashed and burned when we put it to the test," said Neal Barnard, MD, study author and president of the Physicians Committee for Responsible Medicine, in a statement. "The Mediterranean diet caused no weight loss at all. The problem seems to be the inclusion of fatty fish, dairy products, and oils. In contrast, a low-fat vegan diet caused significant and consistent weight loss."