Diet Detective: Much of your work focuses on how we make decisions. Knowing that choosing to eat unhealthy food is a risky decision that can lead to increased risk of cardiovascular disease, diabetes and many other diseases, why would one choose to eat that way?
Dr. Berns: The simple answer is because unhealthy food tastes good. The deeper answer is that knowing that something is bad for you is a different cognitive process than wanting something because it tastes good. The first is an abstract piece of knowledge, while the second is a primitive emotional drive to consume calories. When abstract reasoning collides with primitive impulse, it takes conscious mental effort to override the impulse. We know from studies of brain development that impulse control is a job performed largely by the frontal lobes, which probably don’t fully mature until the mid-20s. Some people may never develop full impulse control. You’re right that the choice to eat unhealthy foods is a decision, but to understand why people make the unhealthy choice we have to look at the elements of this decision.
Diet Detective: Why is it that humans and animals are more likely to take an action leading to an immediate reward than one that would lead to a delayed reward of similar magnitude?
Dr. Berns: This is the first problem we face when choosing between instant gratification of a hungry impulse and the delayed consequences for health. When you eat a chocolate sundae, you immediately feel good. We now know that these positive feelings are associated with the release of the neurotransmitter dopamine. In fact, dopamine is released well in advance of consumption. It is more properly a neurotransmitter of anticipation. When released, it causes the feeling of positive anticipation, and this is what causes you to reach for that spoon and dive in. The dopamine system is like a fuel-injector for action. It mobilizes your motor system to acquire whatever goodies are within your reach. It is also very fast-acting. It doesn’t really consider future consequences. That is the job of the frontal lobes, which have to work overtime to interrupt the dopamine system. We think that the brain evolved this way because it is more advantageous to consume something immediately present than to wait for something possibly better in the future (a bird in the hand…). Every animal on the planet behaves this way — even honeybees.
Diet Detective: What can we do to correct this disconnect between what we say we want and what we actually do?
Dr. Berns: Don’t put yourself in situations in which the insect part of your brain will be activated. Once the dopamine system has zeroed in on those yummy but unhealthy treats, it is almost impossible to stop it. The best solution is to put safeguards in place to prevent temptation. Don’t keep foods in the house that you don’t want to eat. Don’t drive by restaurants that are problem places for you.
Diet Detective: It's been said that we make more than 200 food decisions each day. Are there core concepts to be drawn from decision-making in economics that could be applied to the way we make decisions about food?
Dr. Berns: At any given moment, the brain will make whatever choice it thinks will improve your well-being. Ideally, we would constantly weigh the risks and benefits of every decision with computer-like accuracy. For most decisions, we actually do a pretty good job. We do poorly when the outcomes of a choice are delayed in time or spread over a long period. A healthy decision has no immediate benefit — its benefits accrue over years and with repeated application. Because of this, any individual food choice has marginal impact on your future health, so it is easy to discount and succumb to immediate gratification. It is the same problem as saving for retirement — the goal is large and distant. We can take a lesson from economics and approach diet the same as retirement. Steady, consistent contributions are more important than timing or individual choices.
Diet Detective: You define an iconoclast as "a person who does something that others say can't be done." How can a dieter become an iconoclast? What lessons can dieters take from an iconoclast? How can a dieter learn to think outside the box?
Dr. Berns: Thinking differently begins with perception. Perception is the process by which the brain transforms the senses into mental images that you are aware of. But perception is also a habit. We become accustomed to seeing things a certain way and quickly lose the ability to see people, places and things from new angles. Changing your immediate surroundings can help. Rearrange your kitchen. Put things in different places, change brands — anything that changes the way you see food can change your relationship to it.
Diet Detective: Based on what you say about how the social messages we receive affect our decision making, how might this kind of groupthink impact our decisions to eat more food? To be more specific, does seeing other people eat unhealthy food influence one’s decision to do the same?
Dr. Berns: Absolutely. Some of our brain-imaging experiments have shown that other people’s opinions change the way you see the world. We have seen this for geometric shapes as well as music. It certainly applies to how you see and interact with food. If the people around you eat a certain type of food, that sends strong messages to your brain about collective wisdom. But the group is not always right or acting in your best interest.
Diet Detective: Do you have any suggestions for how people can avoid this kind of behavior?
Dr. Berns: Don’t put yourself in situations with people who will eat in a way you don’t want to eat. Willpower is not as strong as we think it is. It is a better strategy to not tempt temptation.
Diet Detective: When I hear the word “groupthink” I immediately conjure up images of some Orwellian Big Brother figure. Do you think that increased government mandates about food labeling and “full disclosure” on restaurant menus will have a significant impact on our food choices? And, if so, will they be positive or negative?
Dr. Berns: There is a possible benefit for food labeling, but it is worthless in restaurants. It could work for food labeling because this lets consumers make informed choices at the supermarket so that they don’t stock foods that will tempt them later. I don’t think it will work in a restaurant because at that point, you’re already in a high-risk situation. The assault on the senses overwhelms cognitive control (or at least makes it harder than it already is).
Diet Detective: One of your studies showed that when people received “expert” advice, the parts of their brain associated with calculating probabilities and making thoughtful decisions shut down. They tended to simply take the advice of the expert, even when it was bad advice. Given how much conflicting advice we receive every day about what we should or shouldn’t be eating, how do you think that might affect people’s ability to make the best choices for themselves with regard to what they eat?
Dr. Berns: Don’t listen to experts — including me.
Diet Detective: Do you know any ways we can "trick" our brain into eating healthier?
Dr. Berns: There are no tricks. If there were it would be easy and we would all save enough money for retirement, prevent global warming, give up cigarettes and any other vices in which the long-term consequences are delayed. Our brains did not evolve for these types of decisions. For the most part, we have brains that are bound in the present, with only slightly better capacity for remembering the past and projecting the future than monkeys. But just because we can imagine the future, good and bad, doesn’t mean that we automatically choose the best things to do. You have to set up roadblocks to prevent the insect part of your brain from responding to the here and now all the time.