Researchers from Charite — Universitatsmedizin 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 the study published in the Journal Nature publication, the researchers report that dieting results in an increase of specific bacteria — notably Clostridioides difficile, which is associated with antibiotic-induced diarrhoea and colitis.

These bacteria apparently affect the body’s energy balance by exerting an influence on the absorption of nutrients from the gut.

The human gut microbiome consists of trillions of microorganisms and differs from one person to the next. In persons who are overweight or obese, for instance, its composition is known to be different to that found in individuals with normal body weight. Many of us will, at some point in our lives, try dieting in order to lose weight.

But what effect does such a drastic change in diet have on our bodies? An international team of researchers co-led by Charite has addressed this question. “For the first time, we were able to show that a very low-calorie diet produces major changes in the composition of the gut microbiome and that these changes have an impact on the host’s energy balance,” said Prof. Dr Joachim Spranger, Head of Charite’s Department of Endocrinology and Metabolic Diseases and one of the study’s lead authors.