Science!: Dark Matter, Google and Junk Food

Lauren Admire | 26 Oct 2009 17:00

Addicted to Pizza

I like pizza. I mean, I really, really like pizza. I'd even go so far as to say I'm addicted to pizza. It's delicious, it smells great and it reminds me of my childhood, when my Dad, then working as a pizza delivery guy, would bring home fresh pizzas all the time. I crave that greasy, cheesy goodness nearly every day. Thankfully, instead of blaming my nearly non-existent willpower and the development of the Pizza Hut iPhone app, I can just admit the secret, horrible truth: My name is Lauren Admire, and I'm addicted to pizza.

Whew, feels good to finally say it.

This week, scientists have found that rats that consumed a diet high in junk food had brains which mimicked the brains of those addicted to heroin. In the study, one group of rats was fed a reasonable, low-calorie diet. The other group of rats was fed a diet consisting solely of Ho-Hos, cheesecake, bacon and pound cake. (Guess which group I'd prefer to be in.) The rats offered the plethora of junk food quickly became compulsive over-eaters and obese, corroborating recent findings that eating fatty foods cause your body to ignore appetite-suppressing signals.

Researchers Paul Johnson and Paul Kenny decided to test if the over-eating was affecting the pleasure centers of the brain. Rats from both the control and the fast food group ran on an exercise wheel while the researchers stimulated the pleasure centers in their brain. The more they ran, the more stimulation their pleasure centers received. The group of rats on a junk food diet ran the most, which indicates that they needed more brain stimulation to get the same level of "good feelings" that the control group received while running for less time. This is a basic example of habituation. The more junk food, cocaine or sex you receive, the quicker your pleasure centers become used to the stimulation. Once this happens, the pleasure centers require ever increasing amounts of stimulation in order to achieve the same level of pleasure that they received when eating or running less. This is exactly why drug users begin to take larger doses of drugs - they aren't receiving the same "high" that they did before, and they need more of the drug to get the same high.

After five days of eating the junk food diet, rats were acting like druggies on their fifth year of meth (puts the character of Templeton into a whole new perspective, don't it?). Their pleasure centers had been dulled to the point that they needed to eat even more food in order to get the same stimulation that they had when eating less. They became addicted to junk food.

To test exactly how addicted these rats were, the researchers performed another test. In order to get to the delicious piles of junk food, rats would have to endure a shock. Rats from the healthy diet group stopped eating entirely in order to avoid the unpleasant shock. The junk food rats, on the other hand, endured the shock over and over again in order to get to the delectable, tasty treats. Even more alarming, when the junk food was taken away and replaced with salads, the junk food rats refused to eat. "They starve themselves for two weeks afterward," Kenny says. "Their dietary preferences are dramatically shifted." So, the next time you're trying to decide between an apple or a slice of pizza, think twice. Pizza is the gateway food.

Sources: Science News,Discover

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