Getting to obesity’s bottom line

Hunter-gatherer instincts set loose in a world of modern food abundance are at the root of today’s obesity crisis, according to a Harvard psychologist.

Deirdre Barrett, psychologist with the Harvard-affiliated Cambridge Health Alliance and assistant clinical professor of psychology in Harvard Medical School’s Psychiatry Department, says food manufacturers and advertising campaigns play to our Paleolithic instincts. They overemphasize the qualities of certain food items that appeal to the hunter-gatherer in us, creating “supernormal stimuli,” cues on an unnatural object that make it more desirable — and harder to resist — than the natural object it mimics.

Our bodies evolved in a world where salt, sugar, and fat were scarce and desirable. We live, however, in a word where those substances are not only plentiful, but in which images of them in different forms are beamed at us constantly.

“You really can’t just trust your instincts or listen to your body unquestioningly in today’s environment,” Barrett said.

Barrett, who has treated many cases of eating disorder over her years in the field, said she advocates radical change for those seeking to eat healthier and lose weight. Simply cutting down on unhealthy french fries or sugary snacks requires more willpower, she said, than does eliminating them entirely: more painful in the first few days but ultimately easier to maintain.

Barrett’s advice comes in her latest book, “Waistland,” published in July. Barrett said in an interview Tuesday (June 26) in her Cambridge home that for years she looked for a book that said what she felt needed to be said. Finally, she wrote it herself.

“For years I kept not liking the diet and fitness books out there and wanted one like mine,” Barrett said.

Barrett’s career has centered on health psychology, with a focus on dreams and hypnosis. She said she’s treated many patients for eating disorders through hypnosis, but has used more traditional methods as well.

“Waistland” combines scientific findings about the lifestyle and diet of early humans with recent data on the nation’s obesity crisis to shed new light on dieters’ impulses and urges, as well as on what a healthy diet should look like, and how best to stick to one.

Barrett recommends eating whole foods such as dark vegetables, nuts, lean meat, and eggs — and avoiding trans fats, white flour, and processed sugar entirely. She recommends exercising an hour a day and limiting television viewing. She avoids specific diet plans, however, because they take too much time and attention. Don’t buy prepackaged meals, she says, and don’t eat at fast-food restaurants. If your kitchen is stocked with healthy foods, those are the ones you’ll eat.

Barrett doesn’t buy the “there’s no time to eat healthy” argument. Not only does she offer a few fast examples, such as a salad of baby spinach with a can of tuna tossed on top, she points out that while most people complain it takes too much time to eat healthy, most people also watch too much television. Take an hour a day from the average three that adults in industrialized countries watch TV and use that hour to prepare healthier meals; then, you’ll be winning on both counts. When it comes to television, Barrett goes even further, recommending that people shut it off entirely, saying dropping television is an “excellent companion” to a new diet and exercise regime.

Once one switches to a whole foods diet, Barrett says, it takes just days for the cravings for processed foods to fade. And, she writes, if fresh vegetables and steamed fish don’t appeal to you after a few weeks, chances are you’re not hungry. So don’t eat.

“Radical changes are actually easier after the first few days,” Barrett said.

Barrett explains in the book that establishing new eating patterns essentially means establishing new habits. Habitual behavior uses a different part of the brain than novel behavior does. When driving to work along a familiar route, for example, the driving can be handled by the part of the brain dedicated to habits, while the rest of the brain can think about other things. Plying a new route, however, requires other parts of the brain to pitch in and help out. Creating a new diet, Barrett said, entails a similar process. At first, she said, it does require extra thinking and extra effort to decide which foods to include and which not to. Stick with it, however, she said, and soon eating healthy will be as routine as that everyday drive to work.

Barrett is also tough on those looking for excuses not to get healthier. She embraces the idea of willpower, which she said has been given a bad name in some circles in relation to weight control. She also takes on those who believe the problem is not with overweight people, but with societal norms that idealize people with an unhealthily thin body shape.

Not so, writes Barrett, who maintains that over long periods of time, the supposed “ideal” female and male bodies have remained pretty much the same. Instead of attacking the physical ideal, Barrett said, one should focus on one’s other strengths and realize one doesn’t have to be “ideal” to be appealing.

“The tendency to compare oneself to others is ancient and the current tendency to emphasize weight is because that’s become such a common problem,” Barrett writes. “Denial doesn’t help anything — and claiming the average women’s weight is healthy and that models are too thin doesn’t make it so.”

While Barrett offers advice to individuals on how to eat healthier, she also looks at the broader issue of the role society plays in enforcing unhealthy eating habits. Subsidies to the agriculture industry are misguided, she said, fostering an overproduction of corn and corn syrup when they should be encouraging the planting of more healthy foods, such as broccoli. Trans fats are unhealthy and should be banned, she said. Trans fats are one of the easiest problems to address, since unlike a greasy cheeseburger at the local fast-food joint, they’re a relatively invisible part of foods and can be replaced by healthier fats. Junk food should be handled as cigarettes are today, with warning labels and taxes to discourage consumption.