Before Gastric Surgery
Understanding The Normal Digestive Process

To the right is a graphic description of how the digestive process looks prior to weight loss surgery. (Click the picture to view a larger version in a separate window.)

Normally, as food moves along the digestive tract, digestive juices and enzymes digest and absorb calories and nutrients. After we chew and swallow our food, it moves down the esophagus to the stomach, where a strong acid continues the digestive process. The stomach can hold about 3 pints of food at one time.

When the stomach contents move to the duodenum, the first segment of the small intestine, bile and pancreatic juice speed up digestion. Most of the iron and calcium in the foods we eat is absorbed in the duodenum. The jejunum and ileum, the remaining two segments of the nearly 20 feet of small intestine, complete the absorption of almost all calories and nutrients. The food particles that cannot be digested in the small intestine are stored in the large intestine until eliminated.

How Does Gastrointestinal Surgery - Also Called Bariatric Surgery - Promote Weight Loss?

Gastrointestinal surgery for obesity, also called bariatric surgery, alters the digestive process. The operations promote weight loss by closing off parts of the stomach to make it smaller. Operations that only reduce stomach size are known as “restrictive operations” because they restrict the amount of food the stomach can hold.

Some operations combine stomach restriction with a partial bypass of the small intestine. These procedures create a direct connection from the stomach to the lower segment of the small intestine, literally bypassing portions of the digestive tract that absorb calories and nutrients. These are known as malabsorptive operations.

What Are the Weight Loss Surgery Options?

There are several types of restrictive and malabsorptive operations. Each one carries its own benefits and risks.

Restrictive Operations For Weight Loss

Restrictive operations serve only to restrict food intake and do not interfere with the normal digestive process. To perform the surgery, doctors create a small pouch at the top of the stomach where food enters from the esophagus. Initially, the pouch holds about 1 ounce of food and later expands to 2-3 ounces. The lower outlet of the pouch usually has a diameter of only about ¾ inch. This small outlet delays the emptying of food from the pouch and causes a feeling of fullness.

As a result of this surgery, most people lose the ability to eat large amounts of food at one time. After an operation, the person usually can eat only ¾ to 1 cup of food without discomfort or nausea. Also, food has to be well chewed. On the next page there are some pictures and further details on this type of weight-loss surgery.

Malabsorptive Operations For Weight Loss

Malabsorptive operations are the most common gastrointestinal surgeries for weight loss. They restrict both food intake and the amount of calories and nutrients the body absorbs. You will find pictures and further details on the next page.