Restrictive-malabsorptive. These procedures combine a restrictive procedure with a bypass, or sectioning off, of part of the small intestine, which causes a decrease in nutrient absorption.
The most common restrictive-malabsorptive procedure done in the United States is called gastric bypass Roux-en-Y. This procedure promotes weight loss by doing two things. As in the restrictive procedures, the surgeon staples off most of the stomach, creating a small pouch for food. Additionally, the upper part of the small intestine, called the duodenum, is bypassed (click here for an illustration). Normally, some protein, carbohydrates, fats, vitamins, and minerals are absorbed in the duodenum. With the surgery, not only are you eating less, but also less of the carbohydrates, fats, and proteins are absorbed, contributing to weight loss.
One of the main advantages to this type of procedure is that overall weight loss is higher. Long-term studies show that 50% to 75% of excess body weight loss is maintained with this surgery.
One disadvantage is that a condition called “dumping syndrome” can happen if sweet foods or larger-than-recommended portions are consumed. If this happens, a person may experience nausea, vomiting, light-headedness, or diarrhea after eating. The experience is uncomfortable but not medically serious. Deterioration of the band or the staple line, stretching of the pouch to a larger size, and leakage of stomach acid are some of the other potential complications of this operation. In addition, vitamin or mineral deficiencies are common unless supplements are taken diligently.
There are other variations of the combined procedure involving longer segments of the small intestine being bypassed or surgical removal of part of the stomach, but they tend to have more complications.
Many of these procedures can be performed laparoscopically, that is, making a small incision and performing the operation using a fiberoptic instrument inserted through the incision. This results in less pain and scarring and faster healing time. Ultimately, your surgeon will decide which type of surgery best suits your needs.
Success is defined as losing 50% or more of excess weight and maintaining that level for at least five years. Results may vary by the type of procedure being performed and the condition and motivation of the individual. Your ability to exercise and commitment to dietary changes increases effectiveness. Studies show that weight loss is most rapid for the first six months after surgery and generally continues at a lower rate for the next 12 to 18 months.
The majority of people with Type 2 diabetes who have bariatric surgery are able to significantly reduce or discontinue their insulin or oral diabetes medicines after surgery is performed. Normally this happens in the first three months after surgery. Blood sugar levels and HbA1c values normalize. Losing excess weight and keeping blood sugar levels normal can reduce the risk of developing heart disease, stroke, high blood pressure, diabetic nerve damage (neuropathy), diabetic kidney disease (nephropathy), and diabetic eye disease (retinopathy). It may also slow the progression of these complications if a person already has them.
The changes made to the stomach and small intestine require both temporary and permanent dietary changes. As with any major surgery, during the first day or two following surgery, only clear liquids such as broth, gelatin, and clear juices are permitted. When tolerated, and preferably before hospital discharge, other liquid foods, such as thinned hot cereal, strained soups, and milk, are added to the diet. Usually within a week, a person is able to eat more of a variety of foods that have been pureed. Solid foods are reintroduced slowly. Many people find they no longer tolerate foods high in sugar or fat following surgery.