Posts Tagged ‘fat food addiction’

High Calorie/High Fat Food = Addictive!

Monday, March 29th, 2010

According to an article in the Palm Beach Post, scientists at Scripps Florida say rats fed a diet of junk food grew addicted to high-calorie, high-fat fare.

The fat rats became so hooked on junk food that when researchers took away the bad stuff and replaced it with healthy food, the rodents chose to starve themselves.

Scripps Florida scientists Paul Kenny and Paul Johnson say junk food changed the rats’ brain chemistry in the same way that chronic cocaine use alters an addict’s brain function. Their study, published Sunday in the journal Nature Neuroscience, bolsters the increasingly popular theory that Americans’ bulging waistlines can be blamed in part on the addictive attributes of unhealthy food.

As part of three years of experiments, Kenny, an associate professor, and Johnson, a graduate student, served one group of rats healthy, nutritionally balanced fare. Another group got unlimited access high fat snacks from a local supermarket including bacon, sausage, cheesecake, pound cake, Ding Dongs and frosting.

Not surprisingly, the rats fed junk food put on weight and became less active.

More surprisingly, the fat rats exhibited the sort of self-destructive behavior associated with human junkies. The rats would eat junk food even if they knew doing so would result in a mild but distinctly uncomfortable electrical shock to their feet.

When Kenny and Johnson replaced the unhealthy food with the healthy diet the rats had been raised on, the animals refused to eat at all.

“They actually voluntarily starved themselves,” Kenny said.

Kenny blames the same culprit that afflicts cocaine addicts: the brain’s dopamine D2 receptor. The brain releases dopamine in response to enjoyable experiences such as eating cheesecake, having sex or snorting cocaine.

But, scientists believe, too much pleasure skews the brain’s reward pathways by overstimulating the D2 receptor and causing it to shut down. For the rats addicted to junk food, Kenny said, the only way to stimulate their pleasure centers was to eat more high-fat, high-calorie food.

“They’re not experiencing rewards the way they should,” Kenny said. “When you experience that, one way of feeling better is to go back to the junk food.”

As part of his research, Kenny used a virus to essentially block healthy rats’ D2 receptors. Those rats quickly developed compulsive eating habits.

Nearly all the rats given junk food became obese yet many Americans can handle the temptation of easily available junk food.

Kenny says that’s because overeating is driven by not just the genetic factors that make us crave junk food but also by social pressures. Humans know junk food is bad for us, and we try to avoid it. But rats don’t find their impulses tempered by clothes that no longer fit or by books by Dr. Oz, TV shows like The Biggest Loser and movies such as Super Size Me.

“The rats don’t suffer from the same social pressures that we do,” Kenny said.

Source: http://www.palmbeachpost.com/health/scripps-florida-addicted-rats-starved-themselves-rather-than-470310.html



 

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