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)

Thinking Beyond Mediterranean Diets

Excerpts from an editorial by Neal Barnard MD, President of the Physicians Committee published in the Good Medicine Journal, Spring 2021

He came as a patient with excess weight, high cholesterol, diabetes, and severe artery disease to see his physician. He asked his doctor about a vegan diet. But his doctor talked him out of it. Instead, he recommended the Mediterranean diet which “is just as effective and a lot easier to follow.” A year later, I saw him again. The Mediterranean diet had done nothing for his weight, and he was still struggling with diabetes, and high cholesterol.

[Tragically] Many clinicians have bought into the notion that a Mediterranean diet is an easy and attractive way to health. In contrast, they imagine a vegan [-low-fat, whole food] diet as a challenge that patients may not be ready for. “We can’t push our patients too far” is the idea. “We need to meet them where they are.”

Yes, we do need to meet patients where they are. They are in the waiting room. They are waiting for a plan that will help them reach their health goals—whether that means eliminating unwanted weight, reducing medications, or reversing diabetes. 

Physicians Petition White House to Cut US Meat Production to Tackle Climate Crisis

The Physicians Committee has petitioned the White House to update its executive order titled “Tackling the Climate Crisis at Home and Abroad”. This 503(c)(3) non-profit public benefit corporation, headquartered in Washington DC and directed by Neal Barnard MD, has recommended policy changes that could help alleviate the climate crisis in curbing animal agriculture and promoting a plant-based diet.

“The current executive order fails to include steps to stop the detrimental impact of animal agriculture and promote the benefits of plant-based dietary patterns,” says the petition.

A major study recently published in The Lancet Medical Journal concluded that a dietary shift towards plant foods and away from animal products is vital for promoting human health and the health of our planet. The researchers found that food production is responsible for up to 30% of total greenhouse-gas emissions, with animal products accounting for the vast majority –about three quarters—of these effects. The report states that projections for the future show that “vegan and vegetarian diets were associated with the greatest reductions in greenhouse-gas emissions.”

The Physicians Committee‘s petition requests that the White House immediately update its executive order to include the following directives:

The Secretary of Agriculture shall propose a strategy to shift subsidies from meat and dairy products to fruits, vegetables, whole grains, and beans meant for human consumption.

The world’s five biggest meat and dairy producers emit more combined greenhouse gases than ExxonMobil, Shell, and BP, the top three oil production companies, according to a report by GRAIN and the Institute for Agriculture and Trade Policy (IATP). The researchers found that greenhouse-gas emissions from 35 of the largest producers of beef, pork, poultry, and dairy are reaching dangerous levels due to unregulated growth and governmental subsidies to ensure inexpensive production costs and supplies such as animal grain. Research shows that policies that encourage a diet that includes legumes, such as chickpeas, lentils, and peas, would benefit humans and environmental health.

The Secretary of Agriculture and the Secretary of Health and Human Services shall include the climate benefit of a plant-based diet in the 2025-2030 Dietary Guidelines for Americans.

In 2015, the Dietary Guidelines Advisory Committee recommended a shift away from animal products towards plant-based diets for sustainability. The Committee stated that “a dietary pattern that is higher in plant-based foods, such as vegetables, fruits, whole grains, legumes, nuts, and seeds, and lower in animal-based foods is more health-promoting and is associated with lesser environmental impact (greenhouse gas emissions and energy, land and water use) than is the current average US diet.”

The Secretary of Agriculture shall propose a plan to include plant-based meals in the National School Lunch Program (NSLP) and monitor the climate impact on US Dept. of Agriculture commodity foods, including meat and dairy products, used in the NSLP and other federal food programs.

Serving fewer animal products saved Oakland Unified School District in California money and reduced its carbon footprint, according to a case study reported by Friends of the Earth. The school district replaced meat, poultry, and cheese with plant-based foods to reduce its environmental impact. The authors also analyzed purchasing records and greenhouse-gas emissions from schools. A 30% reduction in animal products served resulted in a 14% reduction in the district’s carbon footprint.

(This article was published in the Spring 2021 issue of the Good Medicine Journal of the Physicians Committee of Responsible Medicine, Washington, DC)

Plant-based Diets Reduce Severity of COVID-19

Plant-based diets are linked to less severe illness from COVID-19, according to two recent studies. In a study published in the British Medical Journal Nutrition, Prevention & Health, researchers surveyed health care workers with high exposure to COVID-19 patients across six countries on their dietary habits and COVID-19 outcomes. Participants who followed plant-based diets had a 73% lower chance of moderate to severe COVID-19 illness. On the other hand, those who followed low carbohydrate, high protein diets were 48% more likely to have moderate to severe COVID-19 illness.

Those who followed plant-based diets had higher intakes of legumes, nuts, and vegetables rich in fiber and vitamins A, C, and E that support the immune system and overall health. The authors recommended a plant-based diet that avoids pro-inflammatory foods such as red and processed meat, which are associated with negative health outcomes, to help protect against severe COVID-19.

Kim H, Rebholz CM, Hedge S et al. Plant-based diets, pescatarian diets, and COVID-19 severity: a population-based case-control study in six countries. British Medical Journal NutrPrevHealth. Published online June 7, 2021

Similarly, the smartphone-based COVID-Symptom Study, including 592,571 participants, found that dietary patterns that were highest in fruits, vegetables, and plant-based foods in general, were associated with a 41% lower risk of severe COVID-19 and a 9% reduction of COVID-19 infection of any severity, compared with diets lowest in these foods. 

Merino J, Joshi AD, Nguyen LH et al. Diet quality and risk and severity of COVID-19: a prospective cohort study. doi:10.101/2021.06.24.21259283v1.

Vegan Diet—Plus Soybeans—Stops Hot Flashes

WAVS—the Women’s Study for the Alleviation of Vasomotor Symptoms—found that diet changes can be much more powerful for treating hot flashes than scientists had thought.

In the study, postmenopausal women reporting two or more hot slashes per day were randomly assigned either to an intervention group—consisting of a low fat, vegan diet that included half a cup of cooked soybeans added to a salad or soup each day—or to a control group that made no diet changes for 12 weeks. The study used no hormone medications or extracts.

The results of the study, published in July in the journal Menopause, found that a plant-based diet rich in soy reduced moderate-to-severe hot flashes by 84%, from nearly five per day to fewer than one per day. During the 1-week study, nearly 60% of women became totally free of moderate-to-sever hot flashes. Over-all hot flashes decreased by 79%.

“This is a game changer for women aged 45 and over, most of whom we now know can get prompt relief from the most severe and troubling menopause symptoms without medication,” said Neal Barnard, MD, the principal investigator.

Barnard ND, Kahleova H, Holtz DN et al. The Women’s Study for the Alleveation of Vasomotor Symptoms (WAVS): a randomized, controlled trial of a plant-based diet and whole soybeans for postmenopausal women. Menopause. on-line July 12, 2021.