In the evolving landscape of nutritional science, the Mediterranean diet has long been revered for its correlation with longevity and reduced risk of chronic diseases. Rich in fruits, vegetables, nuts, whole grains, and olive oil, it represents a gold standard in balanced eating.

However, increasing evidence suggests that a vegan diet—avoiding all animal-based foods—may offer similar, if not greater, benefits.

A 2020 review revealed that adopting a vegan lifestyle could lead to at least 11 significant health improvements, including lower risks of heart disease, diabetes, obesity, and various cancers. To further explore these benefits, researchers recently conducted a comparative study between vegan and Mediterranean diets.

“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,” says study author Dr. Hana Kahleova, Ph.D., Director of Clinical Research for the Physicians Committee for Responsible Medicine in Washington, D.C.

A landmark study conducted by the Physicians Committee for Responsible Medicine, published in Frontiers in Nutrition, has positioned the vegan diet at the forefront of dietary recommendations for health optimization. This research uniquely focused on the impact of diet on levels of advanced glycation end-products (AGEs), which are harmful compounds that naturally form in the body when proteins or fats combine with sugars in the bloodstream, a process accelerated by the consumption of animal-based foods and high-heat cooking methods.

The study meticulously compared the effects of a low-fat vegan diet and a Mediterranean diet over a controlled period.

This new research is a secondary analysis of a previous Physicians Committee study comparing a low-fat vegan diet to a Mediterranean diet. Participants were allocated evenly into two groups. The first group followed a Mediterranean diet for 16 weeks, transitioned through a 4-week wash-out period, then shifted to a low-fat vegan diet for another 16 weeks. Conversely, the second group started with the vegan diet for 16 weeks, underwent the same 4-week wash-out, and switched to the Mediterranean diet for the final 16 weeks. Assessments were conducted at the start, weeks 16, 20, and 36 to monitor changes and compare dietary impacts.

The Mediterranean diet in this study was structured around the PREDIMED guidelines, which emphasize a high intake of vegetables (at least two servings daily) and fresh fruits (two to three servings daily), along with a minimum of three weekly servings each of legumes, fish or shellfish, and nuts or seeds. Preference was given to lean white meats over red meats. High-fat dairy products, processed meats, sweetened beverages, pastries, and other processed snacks were discouraged. Extra virgin olive oil (50 g daily) was recommended as the primary source of dietary fat.

The vegan diet was entirely plant-based, including an unrestricted amount of fruits, vegetables, grains, and legumes. This ad libitum diet excluded all animal products and added fats, and participants were supplemented with 500 µg of vitamin B12 daily. Both diets were self-administered without provided meals, and alcohol consumption was limited—up to one daily drink for women and two for men.

Participants maintained consistent physical activity and medication regimens throughout the study, unless advised otherwise by their doctors. Weekly educational classes were held for each diet group, offering nutrition education, recipes, meal plans, and group support, fostering a comprehensive understanding and adherence to the dietary interventions.

The results were telling; participants following the vegan diet experienced a significant reduction in Advanced Glycation End Products (AGEs) by 73%, whereas the Mediterranean diet followers saw no significant change in AGE levels. This reduction is particularly notable because high AGE levels are associated with various age-related diseases including diabetes, heart disease, and renal failure.

The vegan diet also showed remarkable results in weight management. Participants on the vegan diet lost an average of 13 pounds, significantly more than their Mediterranean counterparts, who did not experience notable weight changes. This aspect is especially appealing for those seeking not only health improvements but also effective weight loss solutions.

Beyond AGE reduction and weight loss, the study found:

• Visceral Fat: Greater reduction in visceral fat was observed with the vegan diet compared to the Mediterranean diet.
• Fat Mass: Participants on the vegan diet lost about 7.5 pounds more fat mass than those on the Mediterranean diet.
• Cholesterol Levels: The vegan diet led to a decrease of 15.3 mg/dl in LDL cholesterol and 18.7 mg/dl in total cholesterol, whereas the Mediterranean diet did not show significant changes.
• Insulin Resistance: Improvement in insulin sensitivity and reduced insulin resistance were noted with the vegan diet, with no significant changes under the Mediterranean diet.
• Blood Pressure: Both diets resulted in lowered blood pressure; the Mediterranean diet decreased it by approximately 6.0 mm Hg, and the vegan diet by about 3.2 mm Hg.

The accumulation of AGEs in the body has been linked to several metabolic and degenerative diseases. Vegan diets, which exclude animal products, naturally contain fewer AGEs and are less reliant on cooking methods that promote AGEs formation. Therefore, adopting a vegan diet can be a proactive approach to reduce the overall burden of these harmful compounds.

“The study helps bust the myth that a Mediterranean diet is best for weight loss,” says lead study author Hana Kahleova, MD, Ph.D., director of clinical research at the Physicians Committee for Responsible Medicine.

“Choosing a low-fat vegan diet that avoids the dairy and oil so common in the Mediterranean diet helps reduce intake of harmful advanced glycation end-products leading to significant weight loss.”

Reference: “Dietary advanced glycation end-products and their associations with body weight on a Mediterranean diet and low-fat vegan diet: a randomized, cross-over trial” by Hana Kahleova, Tatiana Znayenko-Miller, Giulianna Motoa, Emma Eng, Alex Prevost, Jaime Uribarri, Richard Holubkov, and Neal D. Barnard, 15 July 2024, Frontiers in Nutrition. DOI: 10.3389/fnut.2024.1426642