Gastric bypass is a surgical operation that results in marked reduction in the size of the stomach. None of the stomach is actually removed. Gastric banding is similar, but in my experience and most experts, does not produce as durable long term weight loss. Gastric bypass attacks the problem of obesity by limiting the volume of food and, therefore, calories that can be ingested. Following the operation, the average patient will be able to eat only a few teaspoons of solid food before becoming full.
Gastric bypass permits normal absorption of food, medicines and vitamins.
These are the two major complications of the surgery. However, a small but real risk does remain because of the very nature of the patients and the difficulty of the operation. Patients who are morbidly obese have a greatly increased risk of death from all causes, especially diabetes, heart desease and lung problems. Many patients, as they reach their late 30's, begin to develop complications of obesity that are impossible to manage without significant long-term weight reduction. The operation is generally not recommended for patients over the age of 55 because the injury to the body from prolonged obesity can no longer be reversed by surgery.