Gastric bypass, the most common bariatric surgery procedure, helps patients lose weight by creating a small stomach pouch and bypassing part of the small intestines. Long-term success depends on permanent lifestyle changes, including following an eating plan, exercising more and taking dietary supplements.
How It Works
Gastric bypass surgery limits food intake by restricting the size of the stomach and blocks calorie absorption by bypassing part of the small intestine. Unlike adjustable gastric banding, a purely restrictive procedure, gastric bypass patients do not absorb some calories so their weight loss is faster. They must, however, be careful to choose their diets wisely or they will regain weight.
Patient Qualifications
Because the benefits of surgery must outweigh the risks, gastric bypass surgery is reserved for morbidly obese patients, according to the University of Rochester. Surgeons use the BMI, body mass index, calculation to measure obesity. A morbidly obese person--someone with a BMI of 40 or greater--qualifies for weight loss surgery even if the individual has no medical problems. Someone with a BMI of 35 or greater with a comorbidity--an obesity-related disease such as high blood pressure, diabetes or arthritis--may also qualify for surgery. Gastric bypass patients must also be healthy enough to survive surgery and make long-term lifestyle changes.
Results
Weight loss after gastric bypass surgery averages 60 to 70 percent of the patient's excess weight by the end of the first year, reports the Society of American Gastrointestinal and Endoscopic Surgeons. After 10 to 14 years, according to Highland Hospital, some patients have kept off 50 to 60 percent of their excess weight. About 75 percent of patients also experience control over comorbidities such as sleep apnea, high blood pressure and type 2 diabetes, notes the Society of American Gastrointestinal and Endocsopic Surgeons.
Risks
Possible complications of gastric bypass during or within the first month include bleeding, wound infection, blood clots, leaking at the surgical site and narrowing of the opening between the stomach and the small intestine, according to Stacey Brethauer, M.D., lead researcher in a study published in the November 2006 issue of the Cleveland Clinic Journal of Medicine. Possible long-term complications include bowel obstruction, gallstones, nutritional deficiencies and ulcers near the surgical site.
Comparison to Other Weight Loss Strategies
Any bariatric surgery procedure helps more with weight loss and health in the morbidly obese than does behavioral and medical management alone, according to the Society of American Gastrointestinal and Endoscopic Surgeons. Comparing the procedures, patients undergoing adjustable gastric banding typically lose less weight--45 to 50 percent of their excess weight--than those having gastric bypass surgery, and improvement of comorbidities is less reliable. However, the BPD, or biliopancreatic diversion procedure, helps patients lose about 70 to 80 percent of their excess weight.
References
- SAGES: Laparoscopic Surgery for Severe Obesity
- ASMBS: ASMBS Allied Health Nutritional Guidelines for the Surgical Weight Loss Patient (PDF)
- Highland Hospital: Types of Surgery
- Highland Hospital: Gastric Bypass Roux-en-Y
- UW Health: Gastric Bypass Roux-en-Y
- Cleveland Clinic Journal of Medicine: Risks and Benefits of Bariatric Surgery: Current Evidence (PDF)
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