Why We Eat Too Much

Ever wonder why you can’t eat just one potato chip? A single slice of pizza? How about a solitary bite of cheesecake or a lone chicken wing? David A. Kessler, 57, a Harvard-trained doctor, lawyer, former Yale Medical School dean and one-time commissioner of the U.S. Food and Drug Administration, believes he has found the answer.

Regular exposure to palatable foods rich in salt, sugar and fat can change the way our brains work, Kessler says in his new book, The End of Overeating (see book excerpt). Famous for taking on Big Tobacco and mandating nutrition labels on grocery-store food, Kessler spent the past seven years interviewing physicians, scientists and food industry executives—and uncovered a vicious cycle. Humans are naturally wired to focus on the greatest stimulation in their environment. And when it comes to food, dishes high in fat, salt and sugar—the ones so popular on the American food-scape—fit the description.

The thought of such foods travels straight to the reward center of the brain, releasing dopamine, the chemical associated with pleasure. Eating foods you crave releases other chemicals, opioids, which provide emotional satisfaction. Over time, these neural pathways are strengthened, and soon enough the whiff, even the mention, of a favorite food sets the cycle in motion. Suddenly, it’s a habit—we don’t know when to stop—something Kessler calls “conditioned hypereating.” It’s an addiction, and as with all addictions, we want, even need, more of our favorite foods to gain the same satisfaction. Give someone a bag of chips, and soon, voila! The bag is empty, proving the slogan “Betcha can’t eat just one.”

Q. You write that the giant food corporations and chain restaurants—Big Food, as you call it—are aware of this cycle and use chemicals and fake food products to create alluring fatty, salty, sweet dishes.

A. They know sugar, fat and salt stimulate. They know people will come back for more of these kinds of foods. Now we know the neuroscience behind it.

Q. Is this book a way to get the ball rolling to regulate the industry?

A. My goal is to change the way Americans look at food—to get to the point where you know that what you’re eating is layered and loaded. Pick any appetizer in an American restaurant. Take Buffalo wings. The fatty part of the chicken is deep-fried in the manufacturing plant and fried again in the restaurant. The red sauce is sugar and fat and the cream sauce is fat and salt. So Buffalo wings are fat on fat on fat on sugar on fat and salt.

Q. Do you believe this kind of awareness will help America’s collective weight problem?

A. If you know your chicken is being bathed in sugar and fat and salt, and you know it has as many calories as a plate of nachos, and you know it’s only going to stimulate you to eat more, that’s a place to start.

Q. So Big Food is the culprit here?

A. The business plans of major food companies have been sugar, fat, salt on every corner, distributed everywhere to eat at any time. But we’ve also made eating acceptable everywhere, at all times. Social norms are very important.

Now we know that our brains are being stimulated—by sugar, fat and salt—and reacting excessively. Up until now, no one had explained that. We hadn’t explained that it’s more than just a willpower issue. But just because your brain is being activated and stimulated doesn’t mean you can’t do something about it.

Q. OK, then how do we recognize if food is controlling us?

A. Ask yourself: “Do I have a hard time resisting highly palatable foods that are high in fat, sugar or salt? Do I rarely feel full? Once I start eating, do I have a hard time stopping? Do I think about food?” You will tell me right away if you have one of those characteristics. Either you instantly say, “Yes, that’s me,” or “No, I have no idea what you’re talking about,” or “I have some of it.”

There’s a small percentage of people—about 15 percent of the American population, I estimate—for whom food is not a very salient stimuli. If they could, they’d take food in a pill. But a vast majority of us have at least some of the characteristics of conditioned hypereating.

Q. In what way does conditioned hypereating function like a drug addiction?

A. The circuits are the same. How those circuits get stimulated is different. Drugs can enter intravenously through the bloodstream or the GI [gastrointestinal] track. But with food, stimuli enter in more of a sensory route. Wiring from our senses stimulates those reward pathways. So, yes, there are commonalities in the pathways that drive both behaviors that are driven by conditioning.

Q. So an overeater is going to have just as hard a time correcting behavior as a drug addict would?

A. When behavior is driven, it’s also highly motivated. And when it’s highly motivated, it’s very hard to stop. That’s true for any stimulating substances.

Q. Don’t we know from the mass media or instinctively that too much sugary, salty, fatty food isn’t good for us?

A. But that only makes it worse. If you’re in this cycle, you’re cued by foods like this. They grab your attention and focus you. What’s your favorite food?

Q. Pizza. Thin crust. Crispy.

A. So there’s a pizza right in front of you, right now. It’s hot, thin-crusted, very crispy. It’s perfect. It’s talking to you. That pizza is there, you’re smelling it and you’re doing this interview. So are you thinking about the next question or are you thinking about the pizza?

Q. Pizza.

A. Right. You’re having an inner dialogue. “Boy, that smells great. But I shouldn’t have that. Boy, that would make me feel good. But it has X number of calories.” Once you enter that inner dialogue, you only amplify the reward value of the food. That’s when obsession starts. If it’s sitting in front of you and you can’t have it, you only want it more.

Q. What about good old-fashioned willpower and going on a diet?

A. People don’t want to hear this, but diets don’t work. If you have that old circuitry laid down, that old learning, sure, you can decrease your food intake and lose weight for 30 days, 60 days, 90 days. But if you have that old neural circuitry and go back into your environment, you’re constantly bombarded with old cues. Of course you’re going to gain the weight back.

Q. Then how do we break the cycle? How can I stop from eating pizza when I know it’s available everywhere I turn?

A. Once you know that this overeating is due to this overstimulation of your brains, you can protect yourself. But once you get stimulated and you’re conditioned to hypereating, if you start eating, forget it. Long term the best way to stop hypereating is to eat in a planned and organized way. If you know what you’re going to eat and you want it, you’re not going to view it as deprivation.

Q. That requires lots of planning.

A. Yes. But the ultimate way to calm down a stimulus–and the hardest—is to change the valence. In other words, you change how you perceive the product. We did this with tobacco.

Q. How so?

A. Tobacco used to have a positive valence. Nicotine itself is reinforcing. Then, you add the swirling smoke, the crinkling of the cellophane, the color of the package, the image of the cowboy smoking. The idea that smoking is going to make you feel better, that it’s going to make you look cool and relieve your stress. What do you end up with? You end up with a highly addictive product. So we changed how people viewed it—we changed the valence from positive to negative. We didn’t change the product.

Q. How big a problem is overeating for our collective waistlines?

A. It used to be you’d gain a few pounds between ages 20 and 40. Then, it leveled off and you’d decrease weight in your 60s and 70s. But now weight over a lifetime continues to rise until you’re over 50. People are also entering their 20s much heavier than we did 20 or 30 years ago. We don’t know where this is heading. Weight is really instrumental, certainly, when it comes to cardiovascular disease, stroke and certain forms of cancer.

Q. Do those over 50 still have time to combat long-standing neural pathways and conditioned overeating?

A. No matter what age you are, if you think of sugar, fat, salt as something you want, there’s nothing I can do to change that. But if you come to view something as more important than sugar, fat, salt … if you want something more, then you can change your behavior. You need to be careful because things get accentuated in older life. You see the consequences of excess weight on mobility. You see cardio and medical conditions playing out in older age. I think the stakes are very great in the older years.

Q. Chocolate chip cookies and dumplings were once your weakness. How did you change?

A. Now when I walk in a food court at the airport, there’s a cartoon in my head. Instead of the names on the stand, I look at it and say, “This one is fat and salt, this one is fat and sugar, this one is fat and sugar and salt.” I also ask if it’s really going to fill me up.

As for the cookies, I had to establish a rule. I have to say, “Take them away.”

Carol Kaufmann is a contributing editor at the AARP Bulletin.