Is Weight Loss Surgery for You? (cont.)

Risks and Side Effects

  • Vomiting. This is a common risk of restrictive surgery caused by the small stomach being overly stretched by food particles that have not been chewed well.
  • "Dumping syndrome." Caused by gastric bypass surgery , this is when stomach contents move too rapidly through the small intestine. Symptoms include nausea, weakness, sweating, faintness, and, occasionally, diarrhea after eating, as well as the inability to eat sweets without becoming extremely weak.
  • Nutritional deficiencies. Nearly 30% of patients who have weight-loss surgery develop nutritional deficiencies such as anemia, osteoporosis, and metabolic bone disease. These deficiencies can be avoided if vitamin and mineral intakes are maintained.
  • Complications. Ten to 20% of patients who have weight-loss operations require follow-up operations to correct complications. Abdominal hernias (ruptures) are the most common complications requiring follow-up surgery. Less common complications include breakdown of the staple line (used to make the stomach smaller) and stretched stomach outlets (when the stomach returns to its normal size).
  • Gallstones. More than one-third of obese patients who have gastric surgery develop gallstones. Gallstones are clumps of cholesterol and other matter that form in the gallbladder. During rapid or substantial weight loss a person's risk of developing gallstones increases. Gallstones can be prevented with supplemental bile salts taken for the first 6 months after surgery.
  • Need to temporarily avoid pregnancy. Women of childbearing age should avoid pregnancy until their weight becomes stable because rapid weight loss and nutritional deficiencies can harm a developing fetus.
  • Side effects. These include nausea, vomiting, bloating, diarrhea, excessive sweating, increased gas and dizziness.
  • Lifestyle changes. Patients with extensive bypasses of the normal digestive process require not only close monitoring, but also life-long use of special foods and medications.

Am I a Candidate?

If you have a body mass index (BMI) above 40 -- which is about 100 pounds overweight for men and about 80 pounds for women -- you are considered severely obese and therefore a candidate for surgery.

Surgery may also be an option for people with a BMI between 35 and 40 who suffer from life-threatening cardiopulmonary problems (for example, severe sleep apnea or obesity-related heart disease) or diabetes. For these people, the risk of death from not having the surgery is greater than the risks from the possible complications from undergoing the procedures.

Keep in mind that as in other treatments for obesity, successful results depend mainly on motivation and behavior. In many cases, patients are required to show proof that their attempts at dietary weight loss have been ineffective before surgery will be approved. A psychological evaluation is considered essential by most doctors to determine your potential response to weight loss and change in body image. Most surgeons require patients to demonstrate serious motivation and a clear understanding of the extensive dietary, exercise and medical guidelines that must be followed for the remainder of their lives after having weight loss surgery. In addition, studies are performed to assess the health of your heart and hormonal systems. Nutritional counseling is also a must before surgery.

For patients who remain severely obese after nonsurgical approaches to weight loss have failed, or for patients who have an obesity-related disease, surgery may be an appropriate treatment option. But for most patients, greater efforts toward weight control, such as changes in eating habits, lifestyle changes, and increasing physical activity, are more appropriate. The following questions may help you decide if weight loss surgery is right for you.

  • Have you tried to lose weight through conventional methods of weight loss. group classes, one-on-one counseling, calorie controlled meal plans, food journals, exercise?
  • Are you well informed about the surgical procedure and the effects of treatment?
  • Are you determined to lose weight and improve your health?
  • Are you aware of how your life may change after the operation (adjustment to the side effects of the surgery, including dramatically different eating habits)?
  • Are you aware of the potential for serious complications from the procedure, the associated dietary restrictions, and the slight chance that the procedure will not help you lose weight?
  • Are you committed to life-long medical follow-up?

Reviewed by the Department of Nutrition Therapy at The Cleveland Clinic.


Edited by Charlotte Grayson, MD, WebMD, August 2004.

Portions of this page © The Cleveland Clinic 2000-2004


Last Editorial Review: 7/14/2005