Researchers from Charité–Universitätsmedizin Berlin and the University of California in San Francisco were able to show for the first time that a very low calorie diet significantly alters the composition of the microbiota present in the human gut. In a current Nature publication, the researchers report that dieting results in an increase of specific bacteria—notably Clostridioides difficile, which is associated with antibiotic-induced diarrhea and colitis. These bacteria apparently affect the body’s energy balance by exerting an influence on the absorption of nutrients from the gut.