Is it possible to turn yourself into someone who would rather have strawberries than strawberry ice cream? Yes, according to the results of a recent brain scan study by researchers at Tufts University and Harvard. With a little effort, it appears that we really can rewire our brains to prefer healthy foods to the addictive, high-calorie choices all around us.
It comes down to our brain’s reward centers. Because finding food was once a struggle, we’ve evolved to anticipate more pleasure from eating high-calorie foods than low. Now, however, high-calorie foods are everywhere we turn, and it’s easy for our reward system to become over-activated, which can lead to cravings, weight gain and addictive eating. What has been disputed is whether this hyperactivation then becomes set in stone, or if our neuronal circuits could be rewired so that the low-calorie foods become the ones that light up our brain’s pleasure centers.
The researchers of this study decided to find out. They tracked a group of obese or overweight men and women as they participated in iDiet, a weight-loss program designed by Dr. Susan B. Roberts, PhD, the director of the obesity laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University. The program taught the men and women how to change their eating and prescribed a diet that emphasized moderately high protein, high fiber and low glycemic-index foods – in other words, foods that are digested more slowly and that can help reduce blood sugar fluctuations and hunger. Another group was not part of the weight-loss program but functioned as a control.
The two groups went through functional magnetic resonance imaging (fMRI) brain scans at the beginning of the six-month study and again at the end. As they were scanned, the participants looked at pictures of healthy and unhealthy foods. For those who were part of the weight-loss program, final results showed changes in areas of the brain associated with addiction and learning. In fact, their scans showed significantly more reaction to healthy, low-calorie foods like grilled chicken and salads and decreased sensitivity to unhealthy, high-calorie ones such as fried chicken and cookies. What did it mean? Their brains now anticipated more “reward” in consuming the good foods than the bad. The group also reported less hunger and lost, on average, close to 14 pounds.
“It was an exciting finding,” says Dr. Roberts. “This is the first demonstration that you can increase the level of appeal for healthy food as well as decrease excitement for junk food.” Until now, the best that could be achieved was through gastric bypass surgery, which has been shown to reduce the desire to eat for pleasure – but the procedure comes with no increase in the pleasure of eating healthy foods.
The study looked only at a small number of obese or overweight participants and more extensive research is planned, but Dr. Roberts says the implications are encouraging for anyone who struggles to make good food choices. If we are able to redefine pleasure in eating – if the foods that make us healthy also become the ones we crave – then we don’t have to rely on willpower alone, she says. Thus, it becomes a whole lot easier to stick with a healthy lifestyle. “People can develop the habit of being hyperresponsive to the foods that they typically eat … fried chicken, burgers, french fries,” she explains. “What the study shows is that you can reverse that to the point where people feel not uncontrollably tempted by those things and more tempted by healthy foods.”
Dr. Roberts says she has seen many successes in those who have gone through iDiet, her commercially-available weight-loss program. “It’s not like this can happen overnight with anyone,” she acknowledges, “but we’ve certainly seen that people can be transformed.” What strikes her most of all is what clients typically walk away with: “One hundred percent of the people come [to iDiet] to lose weight for some reason: They have a wedding or they’ve been put on medications that they don’t want, or they’re feeling old and they want to claw back some years. When they leave the program, I’d say at least 90% say that the most important thing to them is they feel in control of food rather than food controlling them.”