Vegan diet better for weight loss than Mediterranean diet

Key takeaways:

• The vegan diet reduced advanced glycation end-products by nearly three-quarters.
• A vegan diet consisting of vegetables, fruits, grains and beans should be the “go-to” recommendation by PCPs for weight loss, an expert said.

A low-fat vegan diet significantly reduced harmful inflammatory dietary compounds compared with a Mediterranean diet, according to findings from a randomized study.

The results — published in Frontiers in Nutrition — showed a positive weight loss effect among participants who consumed the low-fat vegan diet.

According to Hana Kahleova, MD, PhD, director of clinical research at the Physicians Committee for Responsible Medicine, advanced glycation end-products (AGEs) “are harmful substances that build up in our body as we age and promote inflammation and the development of diabetes, CVD and other chronic conditions.”

Kahleova and colleagues had examined AGEs in two previous studies “and found that a vegan diet reduced the consumption of dietary AGEs compared to a standard American diet,” she told Healio.

“Based on this research, we suspected that a vegan diet would be also more beneficial than a Mediterranean diet at lowering AGEs,” she added. “In this study, we wanted to confirm which foods in a Mediterranean diet contributed the most AGEs and what health improvements would be experienced by avoiding them.”

The researchers conducted a secondary analysis of a randomized cross-over trial, where they assigned 62 participants with overweight to either a low-fat vegan diet or a Mediterranean diet for a 16-week period. After 16 weeks and a 4-week washout period, the groups transitioned to the opposite diet for another 16-week period.

The vegan diet consisted of legumes, fruits, vegetables and grains, whereas the Mediterranean diet consisted of vegetables, fruits, legumes, fish, nuts, extra-virgin olive oil and fish.

Kahleova and colleagues found that the low-fat diet decreased AGEs by 73%, or by 9,413 kilounits of AGE a day, compared with no change from the Mediterranean diet.

These changes in AGEs correlated with weight loss, as participants on the low-vegan diet lost an average of 6 kg (95% CI 7.5 to 4.5) vs. no change in weight loss among participants on the Mediterranean diet.

Study investigators attributed much of the weight loss to reductions in fat mass and visceral fat volume.

According to the researchers, the reduction of dietary AGEs from the low-fat vegan diet mostly came from:

• excluding the consumption of meat (41%);
• minimizing the consumption of added fats (27%); and
• avoiding dairy products (14%).

Kahleova noted that there were several findings that stood out to her.

“While a Mediterranean diet is often considered low in meat, removing that meat led to the greatest reduction in dietary AGEs,” she explained to Healio. “Also, the olive oil in a Mediterranean diet is usually touted for its health benefits, but removing it, along with other added fats from animal products, led to a significant reduction in AGEs.”

The researchers pointed out some limitations in the study. For example, dietary intake was self-reported, in addition to a potential for false-positive findings due to multiple comparisons.

Ultimately, “the go-to recommendation that primary care providers should make to patients looking to lose weight is a vegan diet based on fruits, vegetables, grains, and beans, which is significantly lower in AGEs than a diet containing animal products,” Kahleova said. “It is cost-effective, free of side effects, and beneficial at improving many other health conditions, including heart disease and diabetes.”

References:

• Kahleova H, et al. Front Nutr. 2024;doi:10.3389/fnut.2024.1426642.
• Vegan diet better than Mediterranean diet for weight loss and reducing harmful inflammatory dietary compounds, finds new research. Available at: https://www.pcrm.org/news/news-releases/vegan-diet-better-mediterranean-diet-weight-loss-and-reducing-harmful. Published Aug. 9, 2024. Accessed Aug. 22, 2024.