A new study has revealed that a vegan diet, even when including certain “unhealthy” plant-based foods, leads to greater weight loss than the Mediterranean diet. This research offers new insights into effective diet strategies, emphasizing the benefits of avoiding animal products.
A vegan diet that includes refined grains and potatoes — foods often deemed “unhealthy” — results in greater weight loss compared to the Mediterranean diet, a new study by the Physicians Committee for Responsible Medicine has revealed.
The study, published in the journal Frontiers in Nutrition, examined the impact of plant-based eating on weight loss. The researchers discovered that participants who followed a vegan diet lost more weight than those on the Mediterranean diet, partially due to avoiding animal products and added oils.
“Our research shows that even when a low-fat vegan diet includes so-called unhealthy plant-based foods—as defined by the plant-based diet index—like refined grains and potatoes, it’s better than the Mediterranean diet for weight loss, because it avoids animal products and added oils,” lead author Hana Kahleova, the director of clinical research at the Physicians Committee for Responsible Medicine, said in a news release.
The study is a secondary analysis of a randomized clinical trial involving 62 overweight adults. Participants were randomly assigned to follow a low-fat vegan diet — comprising fruits, vegetables, grains and beans — or a Mediterranean diet, which includes fruits, vegetables, legumes, fish, low-fat dairy and extra-virgin olive oil. They adhered to their assigned diets for 16 weeks without calorie restrictions, then switched to their original eating habits for a four-week washout period before swapping to the opposite diet for another 16 weeks.
The results demonstrated that the vegan diet was more effective for weight loss, as well as for improving body composition, insulin sensitivity and cholesterol levels. The vegan group saw significant increases in their plant-based diet index (PDI) scores, influenced by consuming more plant-based foods overall.
The analysis categorized plant-based foods based on the PDI system — dividing them into “healthful” and “unhealthful.” Foods like fruit juice, sugar-sweetened beverages, refined grains, potatoes and sweets fall under the “unhealthful” category.
The findings suggest that replacing animal products with plant-based foods, and reducing the intake of oils and nuts, may be key strategies for effective weight loss.