In cases of severe weight problems, there are several criteria to consider before choosing the option of medical gastric bypass surgery.

Morbid obesity - when the patient is 100 pounds or more over their appropriate weight or has a BMI greater than 40.

The patient can demonstrate health problems related to their obesity which can improve after significant weight loss.

Failure of diets and other weight loss plans - the patient must demonstrate that the option of dieting has not worked.

The patient must demonstrate a commitment to permanent lifestyle changes after gastric bypass surgery.

Most important, the patient must clearly demonstrate their understanding of both the benefits and risks of gastric bypass surgery.