Sure, M&M's and potato chips are irresistible, but could they be addictive?

A new study in rats suggests that junk food can affect the brain in ways similar to drug abuse. Mirroring human consumption patterns, rats were given unlimited access to food we can find in every corner store -- frosting, bacon, candy bars, donuts, sausage, hot dogs, snack cakes and so on.

Obesity, of course, resulted, according to the study detailed in the journal Nature Neuroscience in March 2010. Two hallmarks of drug addiction also appeared.

First, many dopamine receptors -- important players in the brain's reward pathway -- disappeared, possibly signaling that more food was now needed to reach previous levels of satisfaction. Behavior also changed; eating these foods became top priority. The rats continued eating even after a light warned them that they would get shocked if they didn't stop.

The behavior parallels both that of compulsive eaters and addicts, said study researcher Paul Kenny of Scripps Research Institute in Florida. "They can't control it even when doctors have warned them, and their relationships suffer," Kenny told LiveScience.

Since rats that ate regular food did not experience such changes, the researchers concluded there is something unique about junk food.

"Really try to regulate your access to this type of food," Kenny advised. "It is not as innocuous as you think."

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