Obesity, once seen as akin to laziness and overeating, is now understood as a complex disorder having to do with genetics and hormonal as well as lifestyle factors. People seem to have very different energy requirements; some can eat half as much as others and weigh the same.

By some estimates, as many as 20% of Americans are obese with 6-10% classified as morbidly obese (having a body mass index of 40 or greater, or being more than 100 pounds overweight), a health problem with severe consequences that can include hypertension, diabetes, cardiovascular disease, obstructive sleep apnea, degenerative arthritis, breast and colon cancer, psychosocial problems, and more.

As obesity becomes more recognized as a national problem, more and more treatment options are becoming available when simple dieting and increased exercise do not work. One of these treatments is Gastric Bypass Surgery, a form of bariatric surgery, which gets its name from the Greek words for "weight" and "treatment."

In normal digestion, food moves through the digestive track from mouth to anus while digestive juices and enzymes work to absorb calories and nutrients. From the esophagus (the tube connecting the mouth to the stomach), food arrives in the stomach to be broken down by gastric acid. An average stomach can hold from 3 pints to 1 quart of food at a time. From the stomach, food travels through a sphincter to the duodenum, the first part of the small intestine, where many important nutrients are absorbed. What remains then passes through the rest of the small intestine where more nutrients and calories are absorbed until the waste reaches the large intestine where it is stored until elimination.

Gastric bypass surgery alters this process in two ways, by restricting the amount of food the can be held by the stomach and/or reducing the ability of the body to absorb calories by eliminating part of the small intestine from the digestive process. These procedures are called restrictive and malabsorptive respectively. The most common procedure today is called the Roux-en-Y gastric bypass and it is a combination-form of gastric bypass surgery that both shrinks the stomach and bypasses a portion of the small intestine.

Gastric bypass surgery is a lifeline to those morbidly obese who are facing severe health problems. It involves the shrinking of the stomach by stapling or banding to allow less room for food and the bypassing of part of the intestine responsible for absorbing calories as well as nutrients. The result is that patients who undergo the operation lose weight because they both eat less and their bodies absorb less of what they eat.

The benefits of gastric bypass surgery are extensive and prolonged weight-loss resulting in significantly lowered risks of hypertension, heart disease, diabetes, and other health conditions related to obesity. The risks involve surgical complications, nutritional deficiencies resulting in problems like anemia and osteoporosis, and "dumping syndrome," which is an unpleasant reaction that often occurs when patients who have undergone gastric bypass surgery eat a meal high in simple sugars or fats.