Changes in intestinal microflora in obesity: cause or consequence?

Obesity and the associated metabolic disorders, such as diabetes and metabolic syndrome, have become major public health issues worldwide. Obesity results from a positive energy balance and is associated with decreased microbial diversity in the human gut with lower levels of Bacteroidetes. However, whether changes in the gut microbiota are a cause or consequence in obesity remains to be definitively proven. Experiments using germ-free mice have begun to reveal some mechanisms by which the gut microbiota may affect the development of obesity.