More than 68% of U.S. adults are considered overweight, according to federal statistics recently shared by FDA—with close to 36% of these individuals considered obese. In recent years, however, FDA-approved medical devices have played a greater role in treating obesity. Treatment benefits from these devices may be greater for patients with obesity-related health problems like high blood pressure.

“In the past, there was diet and exercise, and then there was invasive surgery, including gastric bypass surgery and gastric sleeve surgery,” says Jeffrey Cooper, MS, DVM, a branch chief in the FDA’s Center for Devices and Radiological Health. “Today, medical devices for obesity treatment require lifestyle changes and carry certain risks, but their placement can be less invasive.”

Measuring Obesity

Obesity is typically measured by calculating body mass index (BMI), which considers height and weight. A BMI outside the range of what is considered healthy can fall into two categories: overweight or obese. A BMI from 25 to 29.99 is considered overweight. A BMI of 30 or more is considered obese.

Still, the FDA notes that although BMI is a widely used screening tool, it is not perfect. “There are situations where BMI is not an appropriate measure. For instance, muscle weighs more than fat, so an athlete can have a high BMI but little fat,” says Cooper. “However, at this time BMI is a very good, easily accessible, indirect indicator of excess body fat for most people.” Currently marketed FDA-approved medical devices to treat obesity are indicated for obese patients, although specific BMI requirements vary by device.

FDA-Approved Devices to Treat Obesity

Currently, four types of FDA-approved devices are approved to treat obesity in certain adult patients age 18 and older: gastric bands, an electrical stimulation system, gastric balloons, and a gastric emptying system. A health care provider should monitor patients with these devices.

Risks vary for each device but can include nausea or vomiting, bleeding, or infection. Some patients who receive treatment and make lifestyle changes (such as increased physical activity and healthy eating) still may not be able to lose weight or keep weight off.

Gastric Bands

These bands are surgically implanted around the stomach. They limit the amount of food a person can eat at one time and increase digestion time, which helps people eat less.

Electrical Stimulation System

This system is surgically implanted into the abdomen to block nerve activity between the brain and the stomach. It includes nerve electrodes, wire leads, and a rechargeable electrical pulse generator that delivers electrical signals to electrodes. External controllers let the patient charge the device and let health care professionals adjust settings. (The process of electric stimulation is understood, but specific reasons for why this helps with weight loss are unknown.)

Gastric Balloons

These temporary devices include one or two balloons that fill space in the stomach. They’re placed using an endoscope, and then they’re filled with saline and sealed. Balloons should be removed after six months.

Gastric-Emptying System

This recently approved device includes a tube placed in the stomach via an endoscope and a port that lies against the skin of the abdomen. (It’s not approved for use in certain patients, including those who have eating disorders such as bulimia.) A gastric-emptying system is used to drain a portion of the stomach contents into a receptacle 20 to 30 minutes after meals. A health care provider must shorten it as patients lose weight (and girth) so the port continues to lie against the skin. Recipients must thoroughly chew all food, among other lifestyle changes and may have the device removed when they reach their target weight.

Reporting Device Problems

Patients should discuss the benefits and risks of different treatment options with their health care providers so that they can together make the best treatment choice, Cooper says. For instance, some devices—including gastric bands and balloons—require patients to eat much less at one sitting.

And the gastric emptying system requires frequent medical visits to a health care provider who monitors device use and provides lifestyle counseling. Health care providers also should monitor patients for the development of eating disorders; if one develops, device removal may be required.

“People should consider whether they’re willing to make the necessary lifestyle changes,” Cooper says.