The DentalSlim Diet Control device uses magnets to lock a person's upper and lower teeth together, allowing them to only ingest a liquid diet.
The device lets you open your mouth only by about 2 millimeters.
A dentist fits the locking bolts on your upper and lower teeth.
Participants in a trial reported losing an average of 14 pounds in two weeks.
Researchers say the device doesn't restrict breathing and apparently still allows you to speak.
Some people have ridiculed the DentalSlim online, saying it resembles a "creepy" torture device.
But researchers with the University of Otago in New Zealand responded by saying its main intent was not for the general public to slim down, but for those who have a short-term medical need to lose weight quickly, such as preparing for some types of surgery and for managing diabetes.