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This Is Your Brain on Food

  Drs. Danyale McCurdy and A. Janet Tomiyama speak on our mind-body relationship with food
  Drs. Danyale McCurdy and A. Janet Tomiyama

Photography: Ann Johansson

Here is some food for thought: What role does psychology play in obesity? To explore this question, U Magazine brought together two UCLA experts on eating and its associated disorders for a conversation about the struggles so many Americans face in maintaining a healthy diet and the effects of negative societal views about people who are overweight. Danyale McCurdy, PhD, is stafff psychologist with the UCLA Eating Disorders Program and part of the UCLA Fit for Healthy Weight Clinic. She alsof provides counseling and psychotherapy in her clinical practice for pediatric and adult patients with eating and weight disorders. A. Janet Tomiyama, PhD, is assistant professor of psychology at UCLA whose research lab investigates the effects of stress and the impact of social stigma on people who are overweight or obese, along with the potentially negative psychological and biological consequences of dieting. This conversation was the first time the two had met; it was moderated by U Magazine contributor Dan Gordon.

Clearly, we aren’t much different genetically than we were 50 years ago, yet obesity is a much bigger problem in U.S. society today. What has changed?

Dr. Danyale McCurdy: You are correct. Our brains haven’t evolved that much in the last 10,000 years. When food was really hard to find, we were expending lots of energy and not consuming very much. Today, we’re in what we call an obesogenic environment. That means food’s plentiful — for most people in this country that means it is just down the street or around the corner — but our atavistic brains don’t know that. So when we go on a fad diet and are in starvation mode, our brains still think we’re on the barren wasteland, we have to go 20 miles to get to the nearest source of food and we’ve got to have it right now. Meanwhile, the food we consume has become much more calorie-dense and nutrient-depleted. This is especially true of low-cost food, which explains the higher rates of obesity in lower-socioeconomic-status populations. It was actually evolutionarily adaptive to be obese in ancestral times. And then there are so many complicated things that go into eating, whether it’s the cognitive control of making the healthy decisions or the rewarding drive to consume food and the punishing effects of exercise. On top of that, in the past 40 years, we’ve gotten a lot more technologically advanced. Food science has become big — labs are making the most palatable, delicious foods our brains could want.

Dr. A. Janet Tomiyama: I couldn’t agree more about the effects that sugar, fat, salt — individually and in combination — have on the brain. Our society today is fighting an uphill battle with food companies that have billions of dollars invested in finding the perfect combination that will make us reach for more.

Dr. McCurdy: I worked in a lab in Kansas that does brain-imaging research in obesity. A couple of years ago, they published a paper looking at the most popular food logos and their effect on obese kids vs. healthy controls. The obese children showed significantly less brain activation in the prefrontal cortex than the healthy-weight children when they viewed the food-salient images, which may mean they have less cognitive control over their cravings in response to the popular food logos.

Given how difficult it is when we have so many choices in front of us, would you say public-health efforts to change the food environment around us are likely to be more effective than individual strategies?

Dr. Tomiyama: Definitely.

Dr. McCurdy: Much more effective.

Dr. Tomiyama: Another thing that has changed over the last several decades is our stress levels. I do research on comfort eating — it’s the easiest, fastest and cheapest way to make yourself feel better when you’re stressed.

Dr. McCurdy: That is very true. And when you’re stressed, you produce more cortisol, which makes you store more fat in your belly, which actually decreases levels of the leptin hormone and increases ghrelin, making you more hungry. So if you’re stressed, you store fat differently, increasing your appetite. It’s like a drug.

Dr. Tomiyama: One of my studies shows that dieting itself is stressful and increases cortisol. So in some instances, it can be a no-win situation. The interesting thing is that we’re not the only species that does comfort eating. Mice, rats and some primates also, when they’re feeling stressed, will gravitate toward high-fat, high-sugar foods. And that actually does dampen these biological stress-responsive systems. So that kind of eating is not all bad, at least in the short term.

Dr. Tomiyama, you have written about the physical toll of the stigma society places on weight. What are the physical implications of society’s views?

Dr. Tomiyama: It’s become evident that experiencing discrimination on a daily basis, even when it’s not overt, triggers stress processes that can negatively affect health. It’s much less acceptable than in the past to say prejudiced things about women or ethnic minorities, but about people who are overweight ...

Dr. McCurdy: It’s the last acceptable prejudice.

Dr. Tomiyama: Right. And it would make sense that having this blatant societal stigma against how you look has to take a toll on your health by revving up your stress levels. We recently conducted a study that found that to be the case.

Dr. McCurdy: Weight is seen as something you have control over, and in our society, self-control and will power are viewed as virtues. The thinking is that if you can’t control your food, you can’t control anything.

Dr. Tomiyama: What’s interesting about obesity stigma is that normally if you’re in a minority group, you have in-group favoritism, where you like the members of your group.

Dr. McCurdy: We get each other, we’re on the same team.

Dr. Tomiyama: Exactly. But in the case of overweight and obese individuals, we often see in-group derogation. Unfortunately, these messages that overweight or obese people are bad are getting through to everyone. And I think the health component is important here, because it gives people a justifiable reason to not like overweight people. It’s not that I don’t like the way you look, the thinking goes. It’s that you’re unhealthy, and that’s bad.

Danyale, I wanted to get your thoughts on this emerging science on the obesity paradox — how the lowest levels of mortality are at a BMI of 25-to-30, which actually is in the overweight range. By far, the unhealthiest BMI to have is very thin. And so the negative health consequences of being a certain weight, I think, are a bit overstated. Now, if you’re unhealthy you’re unhealthy, but having this laser focus on weight really does people a disservice.


Dr. McCurdy: Yes, it does. There’s also this category called the “skinny fat” — people who look thin or normal weight but who actually have a lot of adiposity because they’re not very fit. They have worse health outcomes than people who have a BMI of 26 or 27. Another thing is how this affects eating disorders. We know that the more obese people there are in a population, the more disordered eating there is, whether it’s anorexia, bulimia or binge-eating disorder. People with binge-eating disorder report so much shame and guilt and eat secretly, and, obviously, if you’re doing that all the time, you’re probably going to consume more food than you would if you were going out socially. So again, it’s this circular reinforcing pattern of the more shame you feel over eating, and the more stigma you feel about your body, the more you’re going to eat alone, and then when you’re alone, you eat more. Of course, there is a genetic component too, just like with obesity. The heritability for obesity is, what, up to 70 percent?

Dr. Tomiyama: It’s as heritable as height. Women also think of themselves as overweight at a much lower weight than men do. The average BMI at which they consider themselves overweight is 23, which is well-below the actual overweight cutoff. So there’s some self-stigmatizing going on.

  Drs. Danyale McCurdy and A. Janet Tomiyama speak on our mind-body relationship with food  
 

Dr. A. Janet Tomiyama, Assistant professor of psychology, and Dr. Danyale McCurdy, Staff psychologist, UCLA Eating Disorders Program Psychologist, UCLA Fit for Healthy Weight Clinic

Dr. McCurdy: There are more obese women than men, but what I’m especially concerned about is that there are dramatically more psychological ramifications for obese women than there are for obese men.
Related to the stigma?

Dr. McCurdy: I think so. And obese adolefscent girls are a lot more likely to attempt or follow through on committing suicide than obese adolescent boys.

Why do so many dieting efforts fail?

Dr. Tomiyama: The first thing I would like to put out there is that focusing on weight as the thing to change is part of what creates the stress in the first place. What we really want to do, and what you, Danyale, are doing, I assume, with your pediatric-obesity work, is trying to get kids healthier overall.

Dr. McCurdy: That’s right. We don’t ever use the words “lose weight” with kids.

Dr. Tomiyama: Everyone always wants to know what works. I always recommend exercise, because that not only is good for you, but it also decreases your stress levels. Of course, if you’re overweight, do you really want to go to the gym and get in some workout gear? So it’s certainly not easy. In terms of why dieting is so often unsuccessful, it’s exactly what Danyale said — evolutionarily, the people who survived were those who were able to hang on to their calories as much as possible. So our bodies are programmed to decrease metabolism way down when we start starving ourselves. I also think there’s a psychological aspect here — when you’re hungry, you can’t think as well. The more rational parts of your brain have to work harder to regulate. And, so, it’s a tough battle to make good food choices when you’re in that state.

Dr. McCurdy: I try to talk to people about a whole lifestyle change. It’s not just making these changes now, it’s opening your mind to having a different future. As opposed to dieting.  People who are successful at maintaining a healthy weight tend to have more cognitive executive control. We make hundreds of health decisions every day. There are so many points where you can make the wrong decision. For people who struggle with this, it’s really hard. If you are a drug addict, you can manage to live the rest of your life without having heroin, but for people with eating disorders, it’s like being a heroin addict who tries to give himself just enough heroin three times a day for the rest of his life to get by. It’s the hardest thing to fight, and I have so much empathy for people who face that battle.

 





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