Potential mechanisms of sleeve gastrectomy for reducing weight and improving metabolism in patients with obesity.

Obesity is a severe medical problem endangering the health of individuals worldwide. Sleeve gastrectomy (SG), one of the most commonly performed bariatric procedures, has been widely applied to the treatment of such patients. Currently, the potential mechanisms underlying the significant weight loss and metabolic improvement after SG have been well studied. First, and most importantly, by removing a large volume of stomach, the SG directly or indirectly restricts food intake. Then, there are alterations in the absorption and metabolism of both macro- and micronutrients, which may benefit or worsen the patients' well-being. Another profound change is enhanced secretion of the satiety gut hormone and reduced secretion of the hunger hormone as a consequence of the operation. Additionally, adjustment of gastrointestinal motility, alteration in the gut microbial community, and an inflammatory response were found after surgery. Therefore, the purpose of the present review was focused on such hypotheses and to compile the accumulated facts on the physiologic mechanism of bariatric surgery so that these results can help improve the understanding of how SG produces substantial weight loss and a significant improvement in the metabolism of patients with metabolic syndrome.