Researchers at UC San Francisco have found that extreme caloric restriction diets alter the microbiome in ways that could help with weight loss but might also result in an increased population of Clostridioides difficile, a pathogenic bacterium that can lead to severe diarrhea and colitis.
Such diets, which allow people only 800 calories per day in liquid form, are an effective approach to weight loss in people with obesity. The unexpected results of this study raise the question of how much the microbiome influences weight loss and which bacteria are significant in that process. The study appears in the June 23, 2021, issue of Nature.