David Kessler on Why We're Prone to Eating Too Much

Salty, sweet, and fatty foods speak directly to our brains; and what they're saying ain't pretty.


For almost all of us, there's at least one food that we can't help but overeat. For David Kessler, former commissioner of the Food and Drug Administration (and foe of the tobacco industry), it was the dumplings in the food court of the San Francisco International Airport. His investigation into why otherwise sane, self-assured, competent people like himself lose their will in the face of dumplings, Chili's latest dessert concoction, or dark chocolate M&Ms encompassed the chemistry of modern food production and the newest discoveries of neuroscience. In The End of Overeating (Rodale, $25.95), he argues that the extraordinarily high levels of salt, fat, and sugar in the American diet reward our brains and thus encourage us to overeat. Here's an edited version of our conversation.

You said the idea for the book came from watching Oprah Winfrey's show?

Yes. Dr. Phil was on, talking to this woman, Sarah, who was highly educated, well dressed, and very successful in all aspects of her life. But she said, "I eat when I'm hungry. I eat when I'm not hungry. I eat when I'm happy. I eat when I'm sad. I don't like myself." I was sitting there trying to listen as a doctor, but I could also relate to what she was talking about from my own experience. I needed to understand what was driving her behavior. What did you think about the causes of overeating before you wrote the book?

I didn't know. I knew it wasn't just a matter of diet and exercise, but I didn't understand it. [Have a look at 10-Week Workout Routine: What About Diet?]

What did you find out?

Well, the prime drivers of overeating are sugar, fat, and salt. Animals will work for sugar. If you add fat, [they'll work even harder]. Second, we found that as you make food more multisensory [with different textures to change "mouth feel," for example, or layering several types of sugar], you continue to activate the brain. The bigger the "roller coaster in the mouth" experience, the more dopamine is continually activated. We used to think that we habituated to that. But we asked people if they experienced lack of control, a lack of satiation, and preoccupation in the face of certain trigger foods. If you extrapolate those results out, there are about 70 million people in the U.S. who self-report those three characteristics of reward-based eating. Finally, we looked at healthy-weight individuals who didn't have this kind of conditioned hyperactive eating. The reward circuits in their brains get activated when you cue the individual [with sounds, smells, or a certain setting related to eating, for example]. But in those who are overweight or obese, there's an amplified response both to cues and to actual consumption. It didn't shut off. [Check out Soft Drinks and Energy Drinks: Too Sweet For Your Own Good.]

What about the people who don't lose control—those odd few who "forget" to eat?

There is a percentage of the population for whom food is not a silent stimulus. For them, meals and eating are almost a chore. It's a small minority, probably about 15 percent overall. We know we're all wired to focus on the most salient stimuli, so for them, the question is what else is capturing them instead of food. What can the rest of us do to change our mind-set?

The most important thing is to understand this cycle of consumption: You're cued to eat, your attention is focused, you're aroused, and then you eat. When you're cued again, you start the cycle again. If you know you're being stimulated, you can get rid of the cues: Move the bread basket; don't drive past your favorite burger place. Second, you can avoid the consumption—just don't put it in your mouth! Third, prevent yourself from feeling deprived. Eat in a structured, planned way. Don't get hungry, because when you're hungry, the reward value of the food is higher. Part of that structure may include making rules—say, you will never have french fries. In the end, though, the best way to cool off the stimulus is to change how it's perceived, from "Fries, I want that!" to "Fries, I don't want that!" Without that shift, there's nothing I can do to help. It has to be internalized. So the chicken you eat at a chain restaurant that has been bathed in this syrupy fat and sugar—is that really what you want? How have social norms changed to support the overeating of salty, sugary, fatty things that used to be occasional treats?

We took down all these barriers; now you can eat anytime, anywhere. It's socially acceptable. We have this constant stimulation, and we're no longer eating for nutrition. We took fat, sugar, and salt, made it very appealing, put it on every corner, and made it socially acceptable to eat. What did we expect to happen? What kind of public policy measures do you recommend?

Once you know about this cycle of consumption, there are implications for the food industry and the government as well as for individuals. We know that these foods are activating the brains of millions of consumers. So the government has a role in education and disclosure, as with school lunch programs. But I wrote this not as a policy book but to connect with and help that woman so she can fight back. [To hear about one public policy proposal, read A Novel Cure for Obesity: Tax Sugary Sodas.]

Do you still crave the dumplings?

You need to eat food that's pleasurable and rewarding. But now I can eat three dumplings and enjoy that. I understand that I'm being surrounded by cues, and I just eat in a much more planned way. The last thing I am is a purist, and I don't want to be giving nutritional advice. But I just try to eyeball things and decide I'd rather eat 300, 400, or 500 calories rather than 700, 800, or 1,200 calories. That's now what I want, rather than huge portions.