Today, the American Society for Bariatric Surgery describes two basic approaches that weight loss surgery takes to achieve change:
- Restrictive procedures that decrease food intake.
- Malabsorptive procedures that alter digestion, thus causing the food to be poorly digested and incompletely absorbed so that it is eliminated in the stool.
Surgeons also may perform combination restrictive/malabsorptive operations that take advantage of the benefits of each procedure. One example of a combination procedure is Roux-en-Y gastric bypass.
Watch this short video to learn how weight loss surgery works
Study Improves Outcomes Over Time
The success of these procedures is based on years of study. Surgeons first began to recognize the potential for surgical weight loss while performing operations that required the removal of large segments of a patient’s stomach and intestine. After these surgeries, they found in many cases patients were unable to maintain their pre-surgical weight. With further study, surgeons were able to recommend similar modifications that could be safely used to produce weight loss in morbidly obese patients.
These procedures have been continually refined in order to improve results and minimize risks. Today’s bariatric surgeons have access to a substantial body of clinical data to help them determine which surgeries should be used and why.
Restrictive weight loss surgery procedures, such as Laparoscopic adjustable gastric banding (LAP-BAND®) and sleeve gastrectomy work by reducing the amount of food consumed at one time. When you feel full, you are more likely to have reduced feelings of hunger and will no longer feel deprived. So, you are likely to eat less.
In restrictive procedures, the surgeon creates a smaller upper stomach pouch with a capacity of approximately .5 to 1 oz. (15 to 30 ml) that connects to the rest of the stomach through an outlet known as a “stoma.” The reduced stomach capacity, along with behavioral changes, can result in consistently lower caloric intake and consistent weight loss.
During recovery, patients must adhere to the strict specific dietary guidelines and restrictions their surgeon prescribes. The effectiveness of a restrictive procedure is reduced by constant snacking or by drinking high-calorie, high-fat liquids. Patients who see the best results from a restrictive procedure are those who learn to eat slowly, eat less, and avoid drinking too many fluids, particularly carbonated beverages. If the patient fails to follow these guidelines, they can stretch the stomach pouch and/or the stoma outlet and defeat the purpose of the surgery.
Failure to achieve the expected level of weight loss is usually the result of a patient failing to comply with the recommended dietary and behavior modifications, such as increased exercise and regular support group attendance.
Malabsorptive weight loss surgery procedures are those that alter digestion. They were developed to work in conjunction with restrictive approaches because restrictive approaches have not always achieved the excess weight loss surgeons and patients anticipated.
Some of these techniques involve a bypass of the small intestine. This limits the absorption of calories, which has been shown to have an overall increase in the loss of excess weight.
Lengthening of the small intestine bypass can increase the risk of complications and side effects. You and your surgeon must determine the risks and benefits over your lifetime with the type of weight loss surgery you choose.
Roux-en-Y Gastric Bypass is a combined restrictive and malabsorptive procedure.