Weight-loss program rewires brain to crave healthy food, scans show

It may be possible to retrain your brain to stop craving junk food, a new study shows. 

Eating too much junk food is like any other addiction, research has shown. After years of gorging on high-calorie, highly processed foods, the brain changes, craving pizza and fries instead of salads and grilled chicken. Experts long thought that once the brain changed, it was permanent. But a new study shows it may be possible to eliminate junk food cravings after six months of healthy eating.

“Most of America has problems controlling their food,” says Susan Roberts, senior scientist at the USDA Human Nutrition Research Center on Aging at Tufts University.

Tufts researchers wanted to determine whether anecdotal reports that participants in a weight-loss program developed by Roberts no longer craved junk food. Were there were actual neurobiological changes in brain? To determine this, The Tufts scientists selected 13 overweight or obese adults—eight who were enrolled in the program called idiet and five who ate regularly—to undergo fMRI scans. Both groups had a scan at the beginning of the study and one six months later. 

While in the fMRI, people looked at pictures of healthy or unhealthy foods, as the researchers examined blood-flow in the brain’s reward center.

During the first scan, the reward center in both groups sparked with activity when they viewed images of high-calorie foods. But after six months, the group in the weight-loss program demonstrated excitement in the reward center when they saw low-calorie foods. 

After six-months of healthy eating, the brain’s circuitry had changed. But it's possible the changes could occur as early as two weeks into the program, Roberts says. 

In addition, the people on the idiet lost an average of 14.1 pounds each, while the people who continued to eat regularly gained almost 5 pounds, on average. 

Results of the study were published Monday in “Nutrition & Diabetes.”

“The MRI is just a metabolic demonstration of what people have been telling us,” Roberts says.

The iDiet allows a menu of comfort foods like lasagne, swapping healthier ingredients such as whole wheat pasta or lower-fat substitutions. It also encourages complex carbs, fruits, and vegetables instead of calorie-dense foods, while cutting anywhere from 500 to 1,000 calories daily. Restrictive diets often fail because people feel hungry or because people missing eating favorite foods, Roberts says. 

“When [diets] tell people to be hungry and tell them to eat food they don’t like, their unconscious brain tells them not to do it,” Roberts says. 

It's unclear whether other diets would create the same brain changes. Tufts is starting a comparative study in October to learn more. 

The current study, while small, presents interesting findings, says Kristin Kirkpatrick, manager of wellness nutrition services at Cleveland Clinics Wellness Institute, who was not involved with the study. She believes the results might help experts “get someone off a donut and onto a Brussels sprout.”

It also highlights how the difficulty of weight loss. Hormones, genetics, lifestyle, environment, sleep quality, and taste bud preference can make weight loss challenging. This shows the brain’s role in it.

“I think any time you talk about food and the brain, it is hard to have that conversation without thinking about the addictive qualities,” Kirkpatrick says. “When you have a doughnut, when you have macaroni and cheese there are neurotransmitters … actual things that create [emotional responses].”