Abstract: Currently, bariatric surgery, which includes restricted intake, malabsorptive and mixed surgeries, is known to be an effective measurement for the durable treatment of obesity and related comorbidities. By changing the anatomy of gastrointestinal tract, bariatric surgery achieves the principles of restricting food intake, reducing food absorption, increasing satiety and prolonging gastric emptying to help patients lose weight and regulate metabolic mechanism. Through the neuromodulation of brain‑vagus‑taste receptors, sensation‑specific satiety can reduce the food intake. The brain‑gut‑microbe axis plays a central role in maintaining homeostasis through neuronal pathways in the brain, vagus, spinal nerves, enteric nervous system and signaling pathways. Bariatric surgery can inhibit the development of hypertension, diabetes, non‑alcoholic fatty liver, cardio-vascular and cerebrovascular diseases in the regulation of body fluids through adipokines, bile acids, hormones and other signaling factors. Therefore, the improvement of metabolic‑related diseases after bariatric surgery is the result of the interaction of multiple factors such as nerves, body fluids, and microorganisms. The authors summarize the literature reports to introduce the mechanism of neural and humoral factor regulation in weight loss and improvement of metabolic‑related diseases after bariatric surgery.