Your Brain on Sugar
All that sugar isn’t just impacting your health, however. It’s messing with your brain, too. If you’ve ever felt like your desire for sweets was akin to an addict’s craving for drugs, your hunch wasn’t far off. In a groundbreaking 2011 study, researchers used functional magnetic resonance imaging (fMRI) to scan participants’ brains in response to either seeing or drinking a chocolate milkshake.
What they found: the changes that occurred in anticipation of the drink and while consuming it were very similar to what’s observed in the brains of people who are addicted to drugs and alcohol.
Much like the cravings for other addictive substances, “a food craving begins with a cue,” says Nicole Avena, PhD, a neuroscientist at the University of Florida in Gainesville. “When we talk about cravings, we’re really talking about memories of things we’ve previously learned. Before ever tasting a substance, its packaging, a menu or a restaurant logo are meaningless. However, once they have been paired with the good taste and reward of food, these things can become cues.” A cue can also come in the form of a smell – like the scent of freshly baked cookies – or emotions like stress or boredom. “Your brain pairs the cue with the food and, over time, a cue becomes the thing that elicits the craving,” Avena adds.
Next, your hormones come into play, says Ashley Gearhardt, PhD, assistant professor of clinical psychiatry at the University of Michigan. The cue triggers parts of the brain associated with pleasure, which in turn release dopamine, a hormone associated with feelings of motivation and desire. Furthermore, dopamine drives us to repeat feel-good behaviors, so once you’ve given into your craving, you may already be reaching for another brownie before you’ve even wiped the crumbs of the first one from your face. This makes it more likely that you’ll crave the food again down the road.
Perhaps the most troubling similarity between addictive substances: recent research has shown that you may build up a tolerance to the effects of sugar over time. “The milkshake study found that people who experienced the most addictive eating behaviors exhibited less activation in the reward regions of the brain that would help them stop eating,” says Gearhardt. “If a sugary food doesn’t give you as much pleasure, or reward, as you expect to get from it, you may continue eating more in an attempt to achieve that level of satisfaction,” she explains. In other words, the more sugar you eat, the more of it you require to satisfy that “fix” – and the harder it becomes to kick the habit.