Function

• Gastric bypass helps obese individuals lose weight by removing a substantial portion of the stomach and upper intestines. The result is a stomach that is about the size of a walnut and a digestive tract that is less able to absorb calories and digest large amounts of food at time. Due to the large incision necessary for this procedure, gastric bypass surgery is extremely high risk and it is estimated by the Mayo Clinic that one in every 300 patients experience fatal complications during the surgical procedure.
  
  

Initial Weight Loss

• After the procedure, the patient will experience incredibly rapid weight loss which persists throughout the first year after surgery. It is not uncommon for patients to lose over 100 lbs. in the first year, and continue to lose at a slower rate throughout the second year. However, after the second year post operation, the body finally adjusts to the effects of the surgery and it is during this time that weight regain will happen.
  
  

Weight Gain

• It is not uncommon for gastric bypass patients to gain 5 to 10 lbs. after two years of substantial loss. This is typically due to the body leveling out, learning to absorb more nutrients and calories, and also a slight stretching of the stomach. However, about 5 percent of patients continue to gain beyond these 10 lbs. due to a variety of factors which can result in significant or total weight regain.
  
  

Cognitive Behavioral Therapy

• The reason patients are susceptible to regaining weight post operation is because the surgery only addresses the biological issues surrounding obesity, and not the mental ones. Most people who reach a morbid level of obesity suffer from binge eating disorders and fundamentally dangerous relationships with food. This is why cognitive behavioral therapy is typically incorporated as a facet to surgical procedure. Counseling can help work through these issues and ensure that the emotional reasons why an individual becomes morbidly obese will not cause them to regain all of the weight.
  
  

Nutritional Factors

• Another culprit for why an individual can regain weight after gastric bypass surgery is this slow but steady inclusion of high fat and high calorie foods into the diet. Additionally, portion sizes which are larger than necessary slowly extend the size of the stomach, allowing more calories to be ingested over time. It is essential that gastric bypass patients follow not only the specific diet outlined by their nutritionists but also adhere to portion sizes to prevent them from regaining weight after gastric bypass surgery.