Vegan vs Mediterranean: Which diet is the best for weight loss?

The Mediterranean diet, which has conquered the world with its flavors and its health benefits, could now be dethroned by the vegan diet, which may be more effective for weight loss and cholesterol control, new research suggests. Image: Tempura/Getty Images

Forget olive oil, fragrant herbs and stuffed vegetables, the Mediterranean diet could soon be overtaken by the vegan diet. While the diets aren’t that far removed from one another, the vegan regime could be a better option for weight loss, controlling cholesterol and insulin sensitivity, according to a new study from the Physicians Committee for Responsible Medicine.

To come to these conclusions, the scientists selected participants who were overweight and had no history of diabetes, and randomly assigned them a vegan or a Mediterranean diet. Half of the volunteers started with a low-fat vegan diet excluding animal products and focusing on fruit, vegetables, whole grains and legumes. The second group started with a Mediterranean diet focusing on fruit, vegetables, legumes, fish, low-fat dairy and extra virgin olive oil, while limiting or avoiding red meat and saturated fats.

Participants’ calorie intakes were not limited, and they did not change their exercise or medication regimes, unless otherwise directed by their personal doctors. Participants followed each diet for a period of 16 weeks, then went back to their regular diets for a four-week “reset” before switching to the opposite group to follow the other diet for an additional 16 weeks.

It’s a knockout for the vegan diet

Published in the Journal of the American College of Nutrition, the results appear conclusively in favor of the vegan diet. The researchers found that within 16 weeks on each diet, participants lost an average of 6 kg on the vegan diet, compared to no significant change for those on the Mediterranean diet. Participants also lost 3.4 kg more fat mass on the vegan diet and saw a greater reduction in visceral fat.

The vegan diet also reduced cholesterol levels, while no significant cholesterol changes were observed on the Mediterranean diet. However, while blood pressure decreased on both diets, it actually decreased more on the Mediterranean diet.

“Previous studies have suggested that both Mediterranean and vegan diets improve body weight and cardiometabolic risk factors, but until now, their relative efficacy had not been compared in a randomized trial,” says study author Hana Kahleova, MD, PhD, director of clinical research for the Physicians Committee. “We decided to test the diets head to head and found that a vegan diet is more effective for both improving health markers and boosting weight loss.”

In light of the results, the researchers point out that the vegan diet is often associated with reduced calorie intake, increased fiber intake, and decreased fat and saturated fat consumption, which may go some way to explaining the conclusions.

“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,” says study author Neal Barnard, MD, president of the Physicians Committee. “In a randomized, controlled trial, 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.” NVG

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