Weight loss surgery or bariatric surgery is a long term solution for obesity and related diseases. Obesity is defined as excess accumulation of fat within the body which can be in the form of subcutaneous fat and visceral fat. Subcutaneous fat is the fat which is deposited under the skin and is the energy reserve of the body in times of fasting whereas visceral fat is the fat inside the abdominal cavity and includes the fat deposits in the omentum, liver, kidney and pancreas. This visceral fat is metabolically active and releases a number of chemicals in the blood which contribute to raised blood cholesterol, high blood pressure and diabetes mellitus. These all diseases are part of metabolic syndrome which is associated with high deposits of visceral fat and abdominal obesity. It is more commonly seen in males and post menopausal women and is associated with sedentary lifestyle and consumption of high calorie food.
Bariatric surgery is a metabolic procedure which restricts the food intake and also results in release of certain hormones which promote fat burning from both the subcutaneous and visceral stores. The dissolution of visceral fat results in lowering of blood cholesterol and blood pressure and also helps in management of blood sugar. In many cases, this surgery can help in complete reversal of diabetes and hypertension. The lowering of blood sugar is a direct result of reduced caloric intake. Also, bariatric surgery especially the gastric bypass, results in rapid transit of food through the gastrointestinal tract which leads to undigested food coming in direct contact with small intestine and release of certain gut hormones called incretins. These incretins in turn stimulate the pancreas to secrete more insulin which results in lowering of blood sugar levels. Moreover, obesity by itself decreases the response of insulin on the target cells and leads to insulin resistance. Weight loss decreases the fat deposits and promotes insulin sensitivity. All these factors help in lowering blood sugar levels and may contribute in reversal of diabetes mellitus.