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Little balloons that are swallowed and then filled with gas can help patients lose weight, researchers said Tuesday, offering one more potential way to treat America’s ever-growing obesity epidemic.

The gas-filled balloons can be removed after a few weeks and seem to cause fewer side-effects than other devices used to fill up the stomach, the researchers told a conference. They’re not approved by the Food and Drug Administration yet, but if they do get approval, they’ll join a mounting list of non-surgical options for treating obesity.

Dr. Shelby Sullivan, MD, inserts an endoscope into the mouth of a patient, routing a balloon to the stomach. There it is inflated to give the patient the feeling of being full after eating. robert boston / Washington University

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While the stomach-filling balloons are not as effective as bariatric surgery in helping people lose weight, the volunteers in the study lost about seven percent of their body weight after six months, which is enough to bring down cholesterol, blood pressure and blood sugar.

“At this point, millions and millions of Americans who have obesity are not being adequately treated,” said Dr. Shelby Sullivan, director of bariatric endoscopy at Washington University School of Medicine in St. Louis. “These devices give us an option that eliminates the need to take medications.”

Sullivan and colleagues tested 387 people, having them either swallow real balloons or sugar pills. A thin tube is used to fill the balloons with air. The system, called Obalan, uses three balloons over time.

“These devices give us an option that eliminates the need to take medications.”

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Everyone got weight loss counseling. After six months, the people who got the real balloons lost 6.8 percent of their body weight, compared to a 3.6 percent loss for those who got the sham treatment, Sullivan told the Digestive Disease Week meeting.

“While patients in our study who used this balloon system had a nearly 7 percent total body weight loss, I believe that, once this system is used in the ‘real world,’ patients will experience more than that,” Sullivan said.

Sullivan and her team have tested a variety of the experimental obesity treatments, including fluid-filled balloons. They all cause side effects, she said, but they all help patients lose weight.

In this trial, 90 percent of the patients had a side effect of some sort, usually vomiting and nausea and sometimes abdominal cramps.

“The symptoms that you get from balloons that are already in clinical practice are much worse,” Sullivan told NBC News.

She said as many as 6 to 7 percent of patients treated with some of the other options that are on the market become so dehydrated from nausea and vomiting that they need intravenous fluids. “That didn’t happen with Obalan,” she said.

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The patients must swallow three balloons because of how much of the stomach’s capacity must be blocked off. They swallow them over time.

The various balloons work not only by reducing appetite, but by slowing stomach emptying, Sullivan said. “We think that helped with weight loss," she said.

More than two-thirds of Americans are overweight or obese, and the problem is getting worse. Obesity raises the risk of heart disease, stroke, diabetes, cancer and other conditions.

Obesity drugs have not been greatly successful in helping people lose weight, although several are now on the market. Several more were removed from the shelves years ago after they were found to cause problems such as stroke.

Diets have been shown to be equally bad at helping people keep off the pounds for long periods of time. But surgical procedures to shrink the stomach have been very successful. One study showed the surgery helped people to lose enough weight to reverse their type-2 diabetes.

Also on Tuesday, the American Diabetes Association and other groups endorsed bariatric surgery as a way to treat type-2 diabetes.