Gastric bypass is considered as one or the most effective operations for sustainable weight reduction.
The stomach will be stapled and then divided, making two different sections: the new small stomach or pouch, and the large bypassed stomach. Part of the small intestine will be separated and attached to the pouch so the food will go right into the small intestine after it goes through the pouch. In this way, Gastric bypass surgery combines the creation of a small stomach pouch to restrict (limit) food intake and construction of bypasses of a big portion of the stomach, the duodenum and other segments of the small intestine to cause mal absorption (decreased ability to absorb calories and nutrients from food). This surgery cuts down the amount of food you can hold at one meal.
The small stomach pouch will hold about half a cup of food. When this pouch is filled with food, it stretches and sends a signal to the brain that you feel full and satisfied and should stop eating. If you try to eat more, you may have nausea or abdominal pain, or you may vomit. This type of surgery is more suitable for sweet eaters, because if they eat too much sugar they may feel a wave of nausea or abdominal cramps and sense of fainting.
Gastric bypass surgery reduces the size of the stomach as well as the ability to absorb calories to help you succeed at long-term considerable weight loss. People who have gastric bypass surgery generally lose two-thirds of their excess weight within two years.