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Brain Imaging May Predict Appetite for Junk Food

New Dartmouth research has wide-ranging implications, including in cancer research

At a time when obesity has become epidemic in American society, Dartmouth scientists have found that functional magnetic resonance imaging (fMRI) brain scans may be able to predict weight gain.

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Eating poorly leads to obesity, which is a significant contributor to the development of cancer. Research indicates that obesity alone is a risk factor for 30 percent of cancer deaths in the United States.

In a study published April 18, 2012, in The Journal of Neuroscience, the researchers demonstrated a connection between fMRI brain responses to appetite-driven cues and future behavior. The research has wide-ranging implications for human behavior and disease, including cancer.

"This is one of the first studies in brain imaging that uses the responses observed in the scanner to predict important, real-world outcomes over a long period of time," says co-author Todd Heatherton, the Lincoln Filene Professor in Human Relations in the department of psychological and brain sciences at Dartmouth College and a member of the Cancer Control Research Program at Norris Cotton Cancer Center. "Using brain activity to predict a consequential behavior outside the scanner is pretty novel."

Obesity is a significant contributor to the development of cancer. Research indicates that obesity alone is a risk factor for 30 percent of cancer deaths in the United States. At a Cancer Ground Rounds at Dartmouth-Hitchcock Medical Center on April 26, Margaret Foti, PhD, MD, the Chief Executive Officer of the American Association for Cancer Research, commented: "Obesity [is] something we really need to work on hard." She specifically cited the cancer-prevention research work being conducted at Norris Cotton Cancer Center as very significant in the effort to reduce cancer rates.

Using fMRI, the researchers targeted a region of the brain known as the nucleus accumbens, often referred to as the brain's "reward center," in a group of incoming first-year college students. While undergoing scans, the subjects viewed images of animals, environmental scenes, appetizing food items, and people. Six months later, their weight was compared with their previously recorded weight and brain scan data.

"The people whose brains responded more strongly to food cues were the people who went on to gain more weight six months later," explains Kathryn Demos, first author on the paper. Demos, who conducted the research as part of her doctoral dissertation at Dartmouth, is currently on the research faculty at the Warren Alpert Medical School of Brown University.

Heatherton and William Kelley, associate professor of psychological and brain science and a senior author on the paper, have a longstanding interest in psychological theories of self-regulation, also called self-control or willpower.

"We seek to understand situations in which people face temptations and try to not act on them," says Kelley.

The researchers note that the first step toward controlling cravings may be an awareness of how much you are affected by specific triggers in the environment, such as the arrival of the dessert tray in a restaurant.

"You need to actively be thinking about the behavior you want to control in order to regulate it," remarks Kelley. "Self-regulation requires a lot of conscious effort."

By Joseph Blumberg. A slightly different version of this article was published in Dartmouth NOW on April 17, 2012.

April 30, 2012