Your Brain May Be Sabotaging Your Diet

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At any given moment, about 45 million Americans are on a diet, and more than 23 million are in recovery from alcohol or drug addiction. Trying to break a bad habit is an uphill battle to begin with in a culture of high stress, heavy substance use, and super-sized sodas. But it turns out, our brains aren’t helping either. A new paper published in the journal Current Biology by researchers at Johns Hopkins University reports that our brains actually push us to stick with bad habits.

It’s all about reward. Junk food, booze, drugs, sex, and gambling all push our brains’ (metaphorical) pleasure buttons, triggering a flood of feel-good dopamine. In some ways, your brain is like a small child. When it gets something good—in this case, a whole lot of dopamine—it wants more. You may know that drugs are bad or that cheeseburgers are not a health food, but your brain doesn’t care. More drugs, your brain tells you. More cheeseburgers. Remember cheeseburgers? We should have one of those. With drugs on it. 

"We don't have complete control over what we pay attention to," senior author Susan M. Courtney said in a press release. "We don't realize our past experience biases our attention to certain things." 

Courtney and her colleagues recruited 20 participants to play a simple computer game. The task: Find specific items on a screen filled with colored objects. The reward: cash. Players got $1.25 for each red object and $0.25 for each green object they spotted. One day later, the players came back in and played again while researchers monitored their brains. This time the players were looking for specific shapes, not colors, and there would be no cash prize.

While the players clearly understood the new terms of the game, their brains automatically focused on red objects anyway—and the dopamine floodgates opened. Eventually, the players were able to find the shapes they were looking for, but it took them longer and they were more easily distracted. (Red!)

"What's surprising here is people are not getting rewarded and not expecting a reward," Courtney said in the press release. "There's something about past reward association that's still causing a dopamine release. That stimulus has become incorporated into the reward system."

It’s not hopeless. Addictions can be overcome, healthy eating can happen, and these new findings may someday help facilitate both. In the meantime, don’t beat yourself up too much.

"I could choose healthy food or unhealthy food, but my attention keeps being drawn to fettuccini Alfredo," Courtney said. "What we tend to look at, think about and pay attention to is whatever we've done in the past that was rewarded."