This almost sounds like a joke -- a study from Washington University in St. Louis is recruiting participants to eat only fast food for three months. They'll be paid $3,500 for their troubles, and enrolled in a weight loss program when the study finishes.

The researchers are hoping to study obesity, and why some overweight people develop diabetes and other diet cardiovascular risk-factors, while other people don't. By eating only fast food, the researchers are able to easily monitor the participant's food intake. Participants can choose from McDonald's, Burger King, Taco Bell, KFC and Pizza Hut.

The participants must gain five percent of their body weight during the course of the study. We're thinking that shouldn't be too hard to accomplish.

Curious if you're eligible? Watch the clip below.

Photo by Flickr user: dno1967b