It’s nighttime, and the cookies are beckoning. Maybe you’re stressed, maybe you’re lonely, maybe your boss, kids or mother-in-law is working on your last nerve. Or maybe you just saw a commercial for chocolate chips and thought, Yeah, a cookie sounds good right about now. So then the bargaining begins. Just one, you think. What’s one cookie? That’s no big deal. What’s not considered: One will probably lead to five, which will lead to another handful, which will lead to emptying the package. By the end, you’re not even tasting the treats. You’re just chewing and swallowing. You eat until every crumb is gone.
If this sounds familiar, you may belong to a subset of overeaters who are addicted to food. While not all obesity experts agree, a steady stream of studies over the past decade suggests that the fatty and sugary offerings so common in the U.S. diet—what researchers call highly palatable foods—hook some people in a way that’s biologically similar to the way cocaine or cigarettes do. “My view is that there’s a population of overweight people who have a problem with highly palatable food the way other people have issues with gambling or crack cocaine,” says Paul Kenny, PhD, associate professor of molecular therapeutics at the Scripps Research Institute in Jupiter, Florida. And like narcotics addiction, food addiction has physical repercussions that help keep you enslaved. “Eating these foods changes your brain in ways that impact your choices,” says Kenny. “Even though you know your eating is unhealthy, your brain is still directing you to these foods.”
Research suggests that 5 to 10 percent of the U.S. population suffers from food addiction; one third to one half of bingers and bulimics are thought to fall into this category. (To see if you meet the definition of a food addict, test yourself with this quiz.) A much bigger group of Americans may be borderline cases, and according to Yale University researcher Ashley Gearhardt, PhD, they have this in common: “It seems that people with some signs of addiction—for instance, they are unable to cut down their food intake when they want to—have different brain patterns in response to food cues than normal eaters.”
Food addiction helps explain why so many people ultimately fail to lose weight on traditional diets. It also implies that help could come from solutions based on brain chemistry rather than food restrictions. “We tend to blame people for not having enough willpower to stick to a diet,” says Gearhardt. “But highly palatable foods are addictive, and white-knuckling your way through is just not going to work.”
Here’s what’s going on in the biology of a food addict—and how an addiction can be overcome.
The Biological Imperative
Kenny has done some of the most persuasive studies demonstrating that in susceptible people, fat and sugar can hook the brain’s reward system. In one pivotal study, he fed rats American favorites like cheesecake, bacon and sausage. The heavier the rats became on this diet, the less they enjoyed their food (as measured by electrodes implanted in their brains). Yet they ate more and more compulsively. This dive in reward-center activity, says Kenny, also happens with rats that compulsively consume cocaine or heroin. As a result of that drop in enjoyment, he argues, both rats and people consume more and more of the cocaine, heroin or food in search of their previous high.
A key to understanding how highly palatable food affects the reward system is dopamine, a neurotransmitter that’s released in the brain whenever we have amazing sex, get high on drugs or enjoy a seriously satisfying snack (especially one with lots of sugar or fat or both). When you do something pleasurable, dopamine is responsible for your urgent desire to do that same thing again.
“It’s this wanting that seems to drive food addiction,” says Gearhardt. In a recent study, she used functional MRI scans (which measure blood flow in the brain) to demonstrate that when food addicts see images of chocolate milk shakes, they have a lot more activity in the brain regions associated with dopamine release than nonaddicts do. “When food addicts get food cues, they likely experience a big dopamine burst in their brains, and that encourages them to want the food more than nonaddicts do,” she says. “Seeing a McDonald’s, for instance, would prompt them to go in even if they’d been thinking about eating healthfully and staying on track just five minutes earlier.” And as we all know, these kinds of cues abound in the United States. “Our environment is filled with readily available, inexpensive, high-calorie, irresistible foods,” notes Joe Frascella, PhD, director of the division of clinical neuroscience and behavioral research at the National Institute on Drug Abuse.
Food-addiction researchers have been studying a particular brain receptor, called the D2 receptor, that responds to dopamine. Our brains are constantly making D2 receptors, but overeating or overconsuming alcohol or drugs interferes with the maturation process of these receptors. As a result, people who are obese or addicted to alcohol or drugs have fewer functioning D2 receptors. And these low levels can lead to all kinds of compulsive behavior, including eating, that are intended to punch up the reward system in the brain.
Kenny’s team at Scripps did an experiment in which it lowered rats’ working D2-receptor levels, then fed them rich food. As soon as the rodents had a taste, they began eating compulsively. More important, they wouldn’t stop—even when threatened. (The researchers had trained the animals to associate a flashing light with a foot shock.) “When the control animals saw the light, they stopped eating because they anticipated danger,” explains Kenny. “But the rats with fewer functioning D2 receptors were so motivated to eat, they ignored the possible negative consequences.” Kenny likens this behavior to that of a crack addict who’s lighting up while the police are banging on the door. “Getting your fix is so important, you can’t stop, and that seems to be the case with these animals with less D2 receptors, even before they became obese,” he says.
Inability to stop is what sets food addicts apart from people who simply enjoy eating and have the love handles and belly pooch to show for it. Food addicts generally don’t savor their food; they devour it. Even when it’s not particularly tasty. Even when they feel full. Still, their personal chemistry prompts them to continue to eat. Compared with those less hooked on food, addicts show far less activity in the lateral orbital frontal cortex, the brain region that tells you when to stop eating. “With food addicts, their brakes don’t work, so they lose control of their consumption,” says Gearhardt.
Here’s where your genes come in: Research says the people most at risk for food addiction are those who already have lower levels of working D2 receptors because there’s some kind of compulsion in their family background. Booze, drugs, sex, porn, shopping, gambling—it doesn’t matter what; the reward circuitry responds the same way. However, your family is only part of the story. “Even without a genetic head start, if you ultimately keep eating highly palatable food, you’re at greater risk of becoming a compulsive eater,” warns Kenny. In other words, your eating behavior can lead to addiction-creating changes in your receptors.
Kicking Your Addiction
Go to any kind of 12-step meeting, and you’ll hear the same mantra: Don’t pick it up. Don’t touch the booze, the crack, the cards, the cupcakes. Because as any reputable program will tell you, the only way to break an addiction is abstinence. Break the addiction, and your number of fully functioning D2 receptors will increase. But when the addiction is to food, you can’t go cold turkey, because, um, you still need to eat.
Don’t worry—you can keep food in your life and still manage to detox, explains Pamela Peeke, MD, lead author of the new book The Hunger Fix: The Three-Stage Detox and Recovery Plan for Overeating and Food Addiction. Instead of getting your dopamine fix from fatty and sweet foods, start getting it from healthier stuff like whole foods, physical activity and regular meditation. “These three pillars can keep your dopamine levels elevated enough to kill the cravings as you’re coming off the junk food and help increase D2 receptors so you can reclaim the reward system,” Peeke says. “Safe dopamine elevation is the recipe for lifelong appetite and addiction control.”
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