Obesity-related healthcare problems are rapidly increasing globally. Obese people are highly related to comorbidities such as diabetes, obstructive sleep apnea, and cardiovascular disease. Obesity can also affect the immune system and produce chronic inflammation. In addition to increasing the risk of infectious diseases, they are more likely to increase the risk of cancer. Bariatric surgery is currently the most effective method for treating morbid obesity. Literature has proven that bariatric surgery not only has excellent weight loss effects, but also can control complications caused by obesity, reduce chronic inflammation, and reduce the risk of infection and cancer.