Scientists: Junk Food Causes a Drug-Like Addiction

This is your brain on junk food, according to new research. (Photo: Getty Images)

Cookies, French fries, donuts—no one would ever accuse junk food of being healthy. But new research has discovered just how bad junk food can be.

The study, published Tuesday in the journal Neuropsychopharmacology, found that saturated fat has a similar effect on our brains as drugs. The more saturated fat we eat, the less we enjoy it…and the more we crave it in order to get the same “high.”

For their research, scientists divided rats —which are used for experimentation because their genetic, biological and behavior characteristics closely resemble those of humans — into three groups. One was fed a low-fat diet with equal amounts of monounsaturated fat (i.e. “good fat”) derived from olive oil and saturated fat (“bad fat”) derived from palm oil, another was fed a diet high in monounsaturated fat, and the third was fed a diet high in saturated fat. Other than types of fat, the diets were all the same in terms of amounts of sugar, protein, overall fat content, and calories.

After eight weeks, the rats had similar body weights, but researchers found that the rats on the saturated fat diet had a “significantly blunted” function of the feel-good molecule dopamine. Essentially, they experienced less pleasure after eating, and tried to overcompensate by eating more fatty food.

Study author Cecile Hryhorczuk tells Yahoo Health that your brain responds in a similar way to saturated fat and drugs, since both trigger the release of dopamine in our bodies. In the long term, our systems get used to the response and we become less sensitive to its effects. “This is what occurs in drug addicts, who develop tolerance and need to increase their dose to reach the same amount of pleasure,” she says. “The same thing happens with high-fat food.”

As a result, she says, people who eat foods high in saturated fat will seek out and eat more foods high in saturated fat in order to get the same “high.”

Related: Your Brain Is Wired to Favor Junk Food — 4 Ways to Override It

Saturated fat is typically found in butter, baked goods, fatty meats, cheese, and fried foods, and research on the negative health effects of the fat has been mixed. Older studies have linked saturated fat with higher levels of the bad cholesterol LDL, as well as an increased risk of developing heart disease.

But a large analysis of previous studies published in the Annals of Internal Medicine last year found there is no evidence that eating more saturated fat leads to a higher risk of heart disease.

However, a small study published in the journal JAMA Neurology in 2013 concluded that a diet high in saturated fat can remove an important chemical in the brain that helps protect against Alzheimer’s disease.

The American Heart Association still recommends limiting your saturated fat intake to get no more than six percent of your daily calories from saturated fat (which is about 13 grams of saturated fat for a 2,000 calorie diet). The association also suggests replacing foods high in saturated fat with those high in good fats, monounsaturated and polyunsaturated fats

But New York City registered dietitian Jessica Cording says that all saturated fats may not be created equal. “You should be limiting your intake of junk food, which contains a lot of other things that aren’t doing you favors,” she tells Yahoo Health. “But researchers are still looking at the effects of whole fat dairy products and coconut, which also contain saturated fat.”

Want to cut back on your saturated fat intake? Take a pass on fried foods and try low-fat instead of full-fat dairy products. If you’re baking at home, Cording recommends substituting pumpkin puree or nonfat Greek yogurt for butter — both have a good texture and taste.

Hryhorczuk cautions that you shouldn’t cut out saturated fat entirely, since your brain still needs it in small amounts for various physiological purposes. But, she points out, people should know that the effects of saturated fat goes beyond weight gain that we can actually see.

Cording says the new research is further evidence that it’s a good idea to space out the amount of junk that we eat. “It makes a case for enjoying certain items like ice cream and cake once in a while rather than constantly trying to seek out more of it,” she says. “You’ll enjoy it more that way.”

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