Читать книгу Keeping the Whole Child Healthy and Safe - Marge Scherer - Страница 20

by Amy M. Azzam

Our kids eat too much—and what they're eating drives them to eat even more. In this interview with Educational Leadership, David A. Kessler, former commissioner of the Food and Drug Administration (FDA) under Presidents George H. W. Bush and Bill Clinton, discusses why so many people overeat and what we can do to help children develop better habits.

In his new book, The End of Overeating: Taking Control of the Insatiable American Appetite (Rodale, 2009), Kessler describes how processed food and changing lifestyles are setting people up for a lifetime of food obsession.

Kessler is a lifelong health advocate. Under his watch, the FDA enacted regulations requiring standardized nutrition labels on food. He's also known for his role in the FDA's attempt to regulate cigarettes. Dr. Kessler is a pediatrician and has served as the dean of the medical schools at both Yale and the University of California.

In your new book, The End of Overeating, you paint an alarming picture of our obsession with food. What exactly is overeating?

The journey for me started with some simple questions: Why does that chocolate chip cookie have such power over me? Once I start eating it, why can't I stop? It's the struggle with eating as much as the overeating that the book tries to explain. Why do we do what we know we don't want to do but end up doing anyway?

I was watching Oprah one night, and there was a well-spoken, well-educated woman on the show who said, "I eat after my husband leaves for work in the morning, I eat before he comes home at night, I eat when I'm happy, I eat when I'm sad, I eat when I'm hungry, and I eat when I'm not hungry—and I don't like myself." Obviously, this woman wasn't eating for fuel or nutrition. The question was, What was driving that woman to eat? And I could relate: I have suits in every size.

So if adults are eating like this, I would assume that children are, too.

Certainly when I grew up four or five decades ago, we used to eat at mealtimes—we didn't snack, or only occasionally. But the average child now eats almost constantly throughout the day. Rarely does that child get hungry. Some call this grazing.

What we've done in the United States is taken fat, sugar, and salt and put them on every corner. We've made food available 24/7, and we've made it socially acceptable to eat anytime. We've made food into entertainment. These cultural effects lead to constant eating. The definition of overeating is eating more calories than you expend—more calories in than out. So you have a net weight gain.

Take the average candy bar. You could eat those 300 calories in two or three minutes. But it could take an hour to work them off. The imbalance over the last 20–30 years has been on the intake side, which raises some questions: What's going on? Why do people feel compelled to eat? And why is it so hard to stop?

So why is it so hard to stop?

Take the vanilla milkshake. What is it about the vanilla milkshake that gets us to keep on drinking it? Is it the sugar, fat, or flavor? Science has shown us that sugar is the main driver. But when you add fat to that sugar, you have more consumption. And combinations of fat, sugar, and salt drive consumption—they stimulate you to come back for more.

Forty or 50 years ago, the U.S. food industry shifted from food that was locally grown to a highly interdependent food distribution network that had many advantages in terms of cost and food safety. But now that food is so highly processed, we're able to dial in the exact amount of fat, sugar, and salt that will make us come back for more.

Does this kind of "food" even meet the criteria for what food is supposed to be?

It used to be that we needed to chew the average bite of food from 20 to 30 times. Today it's a fraction of that. Food goes down in a whoosh. It's almost as though it's predigested. It's like we're eating baby food all the time. We're just constantly stimulating ourselves. We're eating for reward—not for fuel or nutrition.

What's going on today is that combinations of fat, sugar, and salt stimulate the reward circuits and get us coming back for more. The reward centers of our brain regulate such behaviors as eating, drug use, and sexual reproduction. We can now look into the brain. For people who have a hard time resisting their favorite foods, we see that fat, sugar, and salt stimulate their brains. In fact, these substances highjack the reward pathways. You can actually see this activation in their brains.

Are children more vulnerable than adults are?

There's no doubt about that. Let's go through how this works. On the basis of past learning, memories, and experience, you get cued. A cue could be a sight, smell, time of day, or location. For example, I walk down a street that I walked down six months earlier. I've forgotten entirely that on that previous walk, I went into a store that sold chocolate-covered pretzels. Now that I'm back on that street, I start thinking about chocolate-covered pretzels. That's a cue.

You associate these cues with the actual food itself. That cue focuses your attention. It stimulates thoughts of wanting. You get this momentary pleasure from responding to the cue—by eating the chocolate-covered pretzels. The next time you get cued, you do it again and repeat the cycle. The behavior becomes both conditioned (learned) and motivated (driven). Once you lay down those learning circuits and those motivational circuits—certainly if you do it in childhood as it's happening today—they stay with you for a lifetime.

Kids are the most vulnerable. When I was growing up, I wasn't being constantly bombarded by food. It wasn't available on every corner, in every gas station, during most of our waking hours. Now our kids are growing up, not just with food that's been highly developed to be stimulating—layered and loaded with fat, sugar, and salt, which stimulates intake—but they're also constantly bombarded with food cues.

Food has to be rewarding. It has to be pleasurable. But I certainly want food that's going to nourish me, that will make me feel full and give me fuel. I don't want food that's going to keep me coming back for more.

My colleague, Dr. Gaetano Di Chiara, one of the great pharmacologists, studies the effect of cocaine and amphetamine on the brain. He finds that cocaine and amphetamine elevate the brain's dopamine circuitry. Dopamine is the chemical that locks in your attention, that gets you focused on the drugs and drives wanting.

We always thought that food gave you a little bump in dopamine the first time, but the second and third times it did not. So I said to Gaetano, let's not use just one ingredient, let's make the food highly palatable; let's take fat and sugar, put them together, and see whether we can get rises in brain dopamine. And we got exactly that—not only the first time, but repeatedly.

What are the repercussions for childhood obesity in the United States?

Let me give you an example. An average 2-year-old knows how to compensate for his or her eating. If the child eats more calories at lunch, he or she will typically eat fewer calories later on in the day. But by 4 or 5 years old, children lose the ability to compensate because they've been exposed to diets that are high in fat, sugar, and salt. They're now eating for reward—and not for fuel.

The greatest gift you can give someone is to lay down healthy eating patterns from the beginning, to find foods that are rewarding as well as healthy. If you continually expose children to fat, sugar, and salt, they will find these foods to be their friends. They will use them to feel good. If that's the case, it's hard to break the habit. Yes, you can retrain the brain, but you do it by laying down new neural circuitry, new learning on top of old.

How can schools help with laying down this new learning?

Once we understand that the constant availability of fat, sugar, and salt conditions and drives our behavior as well as the behavior of our kids, it has profound implications—for school lunch programs, for vending machines, for when we eat, for how we use food, and for how we educate. The best thing that schools can do is to teach kids about nutrition and help them understand that fat, sugar, and salt—although they taste good for the moment—will only stimulate them to come back for more. That if they use food as a reward or for purposes other than for nutrition and fuel, they're contributing to laying down that neural circuitry. That if they use food to regulate mood, then they're going to be stuck in that cycle for the rest of their lives.

Kids look at that huge plate of food now and say, "That's what I want." That's a hard cycle to break. And it's having a profound effect on their health. In the past, adults would get type 2 diabetes in their 40s or 50s, then live for two or three decades with the disease, developing eye disease, kidney disease, cardiovascular disease, and other complications. But kids are now getting type 2 diabetes—at 10 years old! What's going to be the effect of living, not for two or three decades with the disease, but for four, five, and six decades? That concerns me as a pediatrician.

Limiting where we eat, when we eat, and what we eat is vitally important with kids. But we can't just deprive our kids or give them rules. If kids feel deprived, it's not going to work. You've got to give them the tools so they can understand what good nutrition is so they will want to eat foods that will sustain, satisfy, and nourish them.

There are going to be problems if our kids eat foods layered with fat, sugar, and salt for lunch at school, if they use vending machines there, and if stores around the school also sell products layered with fat, sugar, and salt.

We all got into this jam together. We created this problem in the last four or five decades—and it's going to take all of us to undo it. You can't just do it at home, you can't just do it in the schools—you have to do it together.

Originally published in the December 2009/January 2010 issue of Educational Leadership, 67(4), pp. 6–10.