Obesity is a global epidemic disorder with a multifaceted etiology, including genetics and environmental factors. Obesity has approximately tripled from 1975 to 2016, affecting 650 million adults worldwide, and in 2016, 39% of the world population was overweight[1]. Obesity increases the risk of glucose intolerance, nonalcoholic fatty liver disease, type 2 diabetes, breast cancer, colorectal cancer, and obstructive sleep apnea. Therefore, the study of obesity has always been the focus. As is well known, the rate of metabolism is closely related to obesity. In addition, recent evidence suggests that gut microbiota-derived metabolites are related to weight.

Obesity and Metabolism
More simply, metabolism refers to the rate at human body expends energy or burns calories. Some people with slow metabolism eat almost nothing, but still gain weight. Others have a steady weight no matter what they eat or how much they eat. This is because metabolism is almost a genetic factor that is not changed drastically. Researches have shown that strength training may increase muscle mass and thus increase the rate of metabolism slightly.

Obesity and Metabolites
Recent evidence suggests that gut microbiota-derived metabolites affect many biological processes in the host, including appetite control and weight management. For example, amino acids and their byproducts, lipids and lipid-like metabolites, bile acid derivatives, and other metabolites derived from the degradation of carnitine, choline, polyphenols, and purines are gut microbiota-derived metabolites. These metabolites can affect multiple metabolic pathways in the host, leading to obesity and obesity’s complications[2].