Study: Junk Food Can be Addictive
Editor's note: This is the updated version.
A new animal study published online March 28 in Nature Neuroscience suggests something many Americans would have bet the farm on: that eating junk food can be addictive.
The study showed that rats allowed unlimited access to junk foods like bacon, sausage, pound cake, candy bars and other deplorably unhealthy fare gained weight quickly.
And that’s not all; the worst part is that the rats became so addicted to the junk food, they began compulsively eating it, despite the fact that they received an unpleasant electric shock to their feet if they consumed more than was allowed.
In contrast, rats that were given a healthy diet and only limited access to junk food did not gain much weight; more impressively, they knew when they needed to stop to avoid a junk food hangover.
Paul Kenny at Scripps Research Institute in Jupiter, Fla and colleagues observed that the rats on the junk food diet became so addicted that they went on a hunger strike and refused to eat anything for two weeks after the researchers stopped giving them food with no particular nutritional value.
The researchers found the rats under the influence of junk food the dopamine D2 receptor in the brain's reward system suppressed; compulsive eating soon followed.
To confirm that the suppression of the receptor may be the cause of the junk food addiction, Kenny used a virus to artificially suppress the receptor implicated in addiction to cocaine and heroin that had been previously introduced to other lab rats.
Phenomenally, the researchers observed that these rats soon began eating junk food compulsively.
This is an animal study; the findings may not apply to humans. However, there is that altogether reasonable possibility that they just might.
This is not the only study suggesting that food can be addictive. Corsica JA and Pelchat ML from Rush University Medical Center in Chicago published an article in the March 2010 issue of Current opinion in gastroenterology reviewing previous studies and identifying many foods that can be addictive.
According to the authors, foods that are potentially addictive include sweets, carbohydrates, fats, sweet/fat combinations, and possibly processed and/or high salt foods.
The support for the food addiction theory comes from alterations in neurochemistry (dopamine, endogenous opioids), neuroanatomy (limbic system), and self-medication behaviors, Corsica and Pelchat say.
By David Liu and editing by Rachel Stockton
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