5 Days Of Junk Food Is Enough To Change Your Metabolism, Scary New Research Shows

A study published in the Obesity journal finds some scary information about junk food's ability to mess with your metabolism. 

In fact, after subjects spent just five days on a junk food diet, researchers found evidence of the potential for insulin resistance in the future, and the diet severely diminished the body's ability to oxidize glucose into an energy source.

The small study, conducted on 12 subjects, required the participants to eat a high-fat diet (55 percent) that included things like macaroni and cheese, sausage biscuits, microwavable meals, and lots of butter. The caloric value of these meals in total was equal to the calories in the control diet, a moderate 30 percent fat.

After five days, "The normal response to a meal was essentially either blunted or just not there after five days of high-fat feeding," team researcher Matthew Hulver, department head of Human Nutrition, Food and Exercise at Virginia Tech, told Time magazine. "We were surprised how robust the effects were just with five days."

Prior to the high-fat diet, a normal meal would result in the oxidation of glucose for energy. After five days, "that was essentially wiped out," said Hulver.