During the gastric bypass procedure, the surgeon divides the upper part of the stomach, leaving a much smaller compartment. The new, smaller stomach size is then connected to the small intestine, thus bypassing some of the intestines that take care of calorie absorption. The patient can only eat smaller amounts of food than they were able to eat before the procedure. The new stomach compartment can only accommodate a few ounces of food at a time. The gastric bypass promotes weight loss by both restriction and absorption of fewer calories. Since the body absorbs less nutrients, patients are required to take supplements after gastric bypass surgery.
Benefits of Gastric Bypass Surgery
The expected weight loss in the first 1-2 years after a Roux-en-Y gastric bypass is 60 to 80 percent of the excess weight. Research indicates that after 10-14 years, 50 to 60 percent of weight lost has remained off in many patients following gastric bypass surgery. Gastric bypass produces changes in gut hormones that reduce appetite and enhance satiety. In addition, it improves health conditions due to hormonal changes that are evident soon after surgery (e.g. diabetes, metabolic syndrome).
Considerations for Gastric Bypass Surgery
The benefit of gastric bypass surgery that brings weight loss by decreasing intestinal absorption of food also brings risk of nutritional deficiency. That’s because, instead of following the usual path, food bypasses part of the stomach and small bowel. In addition to complications that can come with surgery, some people see continuing deficiencies of vitamin B12, folate, and iron. In addition, a side effect called "Dumping Syndrome" (sugar consumption causing abdominal cramping and diarrhea), can also result. And unless patients make permanent lifestyle changes, they may regain weight in the years following surgery.