Researchers at Scripps Clinic in San Diego, and at other sites, are doing the testing.
The device, called VBLOC Therapy, is surgically inserted into the abdomen and blocks signals from the Vagus nerve, which is the nerve that sends hunger signals to the stomach.
"This device is placed inside your stomach inside the abdominal cavity but then you wear something over it that actually controls it like a belt and this belt will then signal to that device to work," says Dr. Ken Fujioka from the Scripps Clinic.
If the device works, it may be able to go to the FDA soon.
Obesity is a growing problem affecting nearly a third of Americans.