Gastric bypass is a mixed laparoscopic procedure, because it not only restricts but also promotes absorption changes.
It consists in the modification of the digestive tract, by dividing the stomach into two parts, a small (30 ml) stomach pouch, and the remaining of the stomach which is not removed from the body, but is completely stapled shut and divided from the stomach pouch. The outlet from this newly formed pouch empties directly into the small intestine, thus bypassing calorie absorption. This way, you will eat about 30% of your regular diet, absorbing about 60% of your total caloric intake; which will allow you to gradually lose weight.
Gastric bypass surgery is performed under general anesthesia, it lasts approximately 2.5 hours and requires two to three nights of hospital stay. The loss of excess weight during the first year will be on average 90%. Gastric bypass has shown better results than purely restrictive surgeries.
Nutritional counseling will be required after the procedure. You will be prescribed some vitamin supplements to ensure a healthy weight loss, and same as with all weight loss procedures, exercise is important to improve physical fitness, to preserve muscle mass, and to enhance weight loss.
Gastric bypass is the most practiced obesity surgery worldwide, and has delivered the best long term results in terms of weight loss and maintenance of the lost weight. Besides, it improves and in somecases has even cured obesity related health conditions (type 2 diabetes, hypertension, hyperlipidemia, etc.)