DEAR DOCTOR K >> I'm very overweight. Diet and exercise help a little, but then I gain it back. My doctor is recommending weight-loss surgery. Does it really work, and how does it work?
DEAR READER >> There are several types of weight-loss surgery (also called "bariatric surgery"). They work in various ways. They shrink the size of the stomach — the stomach gets full more easily. They reduce the absorption of calories and nutrients in the intestine. Some types of bariatric surgery also lead to hormone changes that reduce appetite and burn energy more efficiently.
One procedure is called gastric banding, or "Lap-Band." Gastric banding involves placing an adjustable band around the stomach to make it smaller. This restricts the amount of food you can eat and makes you feel full faster. The band can be tightened or loosened as needed, depending on how quickly you are losing weight. This surgery is done laparoscopically, through small incisions, using smaller instruments.
Another common weight-loss surgery is known as gastric bypass, which shrinks the size of your stomach. It also reconfigures your small intestine so that food bypasses most of your stomach and the upper part of your small intestine. As a result, your body absorbs fewer calories. Gastric bypass can be done through open surgery or laparoscopically.
Weight-loss surgery can dramatically:
• Reduce blood sugar levels
• Lower blood pressure and cholesterol
• Improve sleep apnea
• Improve heart function
• Reduce symptoms of acid reflux (GERD)
• Reduce urinary stress incontinence
But it's not for people who need to lose just a few pounds. Weight-loss surgery is intended for people who are severely obese, with a body mass index (BMI) of 40 or higher. (BMI is an estimate of your body fat calculated from your height and weight. If you type "BMI" into a search engine, you'll find tools that make it easy for you to calculate your BMI.) In people with a BMI of 40 or higher, the surgery can lengthen life, although the evidence for this is stronger in women than in men.
You can also qualify for surgery if you have a BMI of 35 to 39.9 along with an obesity-related medical condition such as diabetes or heart disease.
Don't think of weight-loss surgery as an easy fix. You must make a lifelong commitment to healthy eating in order to achieve lasting weight loss. Without this lifestyle change, surgery will either make you miserable or not result in weight loss. And most likely, both.
Dr. Komaroff is a physician and professor at Harvard Medical School.