Weight Loss is Associated with Changes in Gut Microbiome: A Randomized, Cross-Over Trial Comparing a Mediterranean and a Low-Fat Vegan Diet in Overweight Adults.

Background: Mediterranean and vegan diets improve body weight and gut microbiome composition. The aim of this study was to compare both diets head-to-head. Methods: Randomized cross-over trial, conducted February-October 2019. Sixty-two overweight adults were assigned to each diet for 16-week periods in random order, separated by a 4-week washout. Body weight was the primary outcome. Secondary measures included changes in gut microbiome which was measured using 16S rRNA sequencing. Results: Body weight decreased on the vegan compared with the Mediterranean diet (treatment effect -6.0 kg [95% CI -7.5 to -4.5]; p Conclusions: A low-fat vegan diet lead to a greater weight loss compared with a Mediterranean diet. This may be partly explained by the difference in gut microbiome composition. Disclosure H. Kahleova: None. R. Holubkov: Advisory Panel; Self; National Institutes of Health, U. S. Food and Drug Administration, Board Member; Self; Pfizer Inc., Revance Therapeutics. N. Barnard: None. Funding Physicians Committee for Responsible Medicine