I always hear my friends around me talk about the paragraph: people can eat about 9 tons of food in their lifetime, who eats first who goes first! Indeed, the negligence in diet makes us change our body shape rapidly and become obese people smoothly, but could obesity be the culprit that causes us to “go first”? On October 3, 2017, the U.S. Department of Health reported that obesity is associated with 40% of diagnosed tumors. This actually included thirteen different types of tumors: brain tumors, multiple myeloma, esophageal tumors, postmenopausal breast tumors, thyroid tumors, gallbladder tumors, stomach tumors, liver tumors, pancreatic tumors, kidney tumors, ovarian tumors, uterine tumors and colon tumors. According to the U.S. Centers for Disease Control and Prevention, they believe that obesity does not mean that it can cause various tumors, but that there is a temporary unexplained association between the two. Even so, the study found that in 2014, more than 630,000 tumor patients in the United States were associated with obesity. Why does obesity cause tumors? Obesity must be accompanied by unhealthy diet and poor lifestyle such as too little exercise. Long-term unhealthy diet will cause a lot of heat metabolism in the body, and too little exercise will hinder the metabolism and increase the blockage of the orifices. 80% of tumors are related to diet. Obese patients tend to prefer high calorie, high animal fat, high trans fatty acid and refined carbohydrates, while the intake of dietary fiber, whole grain carbohydrates, vegetables and fruits is insufficient. Moreover, obese patients generally have too little physical activity, usually lower immune function, weaker disease resistance, and increased risk of tumor development. In addition, the accumulation of abdominal fat in obese patients puts the body in a chronic inflammatory state, and the chronic inflammatory state can induce the occurrence and development of tumors. Overweight and obesity will directly lead to insulin resistance, thus causing compensatory insulin secretion by the pancreas, causing hyperinsulinemia, affecting the regulatory cycle of cell growth and accelerating the occurrence of malignant tumors. Clinically, more than 95% of obesity belongs to simple obesity, which is simply caused by eating too much and too little activity. Therefore, as long as weight loss is successful, the risk of tumor development can be reduced. As for people with high BMI, having weight loss surgery is the only effective way to obtain long-term effective weight loss and to prevent related complications, such as tumors. In the long term, patients can generally lose 50% to 60% of their body weight after the implementation of weight loss surgery, and a 14-year long-term study also showed that the results from weight loss surgery are sustainable.