The Mediterranean Diet Myth: New Study by the Physicians Committee Reveals the Facts

Jenine had extra weight she wanted to lose. She was on medications to lower her cholesterol and blood pressure; she had inflammation in her knees, and she was tired and sluggish much of the time.

That’s when she heard about a Physicians Committee clinical research study comparing the Mediterranean diet with a low-fat vegan/whole food diet to see which was more effective for weight loss and heart health.

Half the participants were to be assigned to a Mediterranean diet, while the others were to start a vegan-whole food diet. After 16 weeks, they would switch to the opposite diet—giving all participants a chance to test both diets and allowing the research to compare them head-to-head.

The Mediterranean diet proved to be a failure. It did little to improve her health. But after switching to the vegan-whole food regimen, Jenine began quickly losing weight and experiencing other health improvements.

“The vegan-whole food diet was way better for me. I lost more weight—about a pound a week—and felt better.,” says Jenine. “I think I’m getting rid of all the animal products and the dairy especially, as well as the refined foods. You see, the vegan diet emphasizes a low-fat regimen, while on the Mediterranean diet you eat a lot of fat.”

She was able to stop taking medicines for cholesterol, blood pressure, and heartburn. Other participants reported similar results.

 

Vegan beats Mediterranean

The vegan diet used in the study eliminated animal products and focused on fruits, vegetables, whole grains, and legumes while minimizing the use of added oils. The Mediterranean diet followed the protocol used in the classic Mediterranean diet study (PREDIMED), which focuses on fruits, vegetables, legumes, fish, dairy products, and extra-virgin olive oil, and includes limited amounts of red meat and eggs.

Neither group had a calorie limit. Participants did not change exercise or medication routines unless directed by their personal physicians. They followed each diet for separate 16-week periods.

 

Dramatic Results

The results were dramatic. Participants lost an average of 13 pounds on the vegan diet compared with no significant weight loss on the Mediterranean diet. The vegan diet also decreased total cholesterol by nearly 19 points, compared with only 3 points on the Mediterranean diet. The findings were published in the Journal of the American College of Nutrition (Barnard ND et al. 2021; 1-13.)

“Previous studies have suggested that both Mediterranean and low-fat vegan-whole food diets improve body weight and overall health. But until now, their relative efficacy had not been compared in a randomized cross-over 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 the vegan diet is more effective for both weight loss and cholesterol control.”

 

Mediterranean Diets Fail in Weight Loss Studies

The Physicians Committee’s study confirms the findings of the Lyon Diet Heart Study and PREDIMED studies, showing that a Mediterranean diet is not effective for weight loss, unless calories are restricted, or exercise is added to the program.  In the PREDIMED study weight loss over the first three study months was barely half a pound, even though 90% of the participants had excess body weight at the start of the study. In the Lyon Diet Heart Study, a Mediterranean diet caused weight gain.

And Jenine?

“The study is over. But I’ve decided to stay vegan. It’s doing too many good things for my body. I feel stronger and better. When I was eating the way I used to eat, I would hit a wall at 2 pm,” she says. “Learning how to eat better has made a huge difference in my energy, and the inflammation in my knees has gone down. So, when I come back from teaching Zumba, I’m not crawling up the steps anymore because my knees hurt so bad. I’m now just walking up normally.”

(Published in the Spring 202 issue of the Good Medicine Journal of the Physicians Committee)

     

Vegan Diet Beats Keto Diet for Weight Loss

A vegan diet is more effective for weight loss than following a ketogenic diet, according to a recent study in Nature Medicine (Hall KD et al. 2021; 27 (2):344-353).

Led by KD Hall, MD, researchers at the Metabolic Clinical Research Unit of the National Institutes of Health, randomly assigned 20 participants to either a low-fat vegan-whole food diet or a low-carbohydrate diet high in fat and animal products but low in sugar and starch for a two-week period. They carefully tracked the calorie intake, body weight, blood sugar, and other biomarkers of the study subjects. They then switched them to the other diet for an additional two weeks for comparison.

Results showed that participants consumed up to 700 fewer daily calories during the low-fat, plant-based diet when compared with the low carbohydrate diet.  But there were no differences in satiety: the vegan diet allowed people to eat less food without hunger. While both groups lost weight, only the low-fat diet resulted in significant reductions in body fat.

Dr. Hall’s presentation at a recent major Conference on Nutrition in Medicine can be viewed at Nutrition CME.org “Keto Controversy: What you need to know.”

(Both research summaries published in the Spring 202 issue of the Good Medicine Journal of the Physicians Committee, Washington, DC)