Cath Hunt- finding a cause of obesity, one m & m at a time

Do you belief that diet and exercise programs simply do not work? Maybe what you need is a mental workout.

There has been a lot of publicity recently relating about obesity in Australia. Various surveys show dire results for the Australian population now and in the future. Many different factors have been blamed for causing the epidemic, from kids not getting exercise, to parents giving kids too much junk food. But what if the answer to the obesity epidemic is located in the brain?

PhD student, Cath Hunt from the ANU's School of Psychology is currently investigating the link between overeating and activity in certain areas of the brain. The brain is divided into two hemispheres, the left and the right. It has been known for some time that certain tasks cause greater activity in one hemisphere than the other. For instance, language is considered a left hemisphere activity, whilst reading a map leads to activation of the right hemisphere.

In individuals, one hemisphere is more active than the other most of the time. Ms Hunt believes that people who have a more active right hemisphere are more likely to overeat and become obese.

"People who have greater right hemisphere activity tend to process information as a "big picture" which means the finer points of information often get overlooked", Ms Hunt explains.

People who process information as "big picture" also tend to be focused on achievement and gains in their life in general. Ms Hunt believes this focus can cause people to overeat.

"It has been found that people who focus on achievement and gains are also more likely to take risks which I believe includes overeating," Ms Hunt said.

Ms Hunt is quick to point out however that the cause of overeating and obesity is not because of the way people with obesity think.

"There are numerous factors that cause a person to overeat and become obese. A good diet and regular exercise are crucial to maintaining a healthy weight," Ms Hunt concedes. "But with any luck, changing the thinking patterns of people with obesity will help some of them in their battle to lose weight."

Ms Hunt is testing her theory by giving participants (ANU psychology students) in her current experiment a task that intends to activate either the right or left hemisphere. During the task, a bowl of confectionaries (M & Ms) is left on the side of the desk. Participants are told the bowl is there purely in case they feel hungry during the task. At the conclusion of the task, Ms Hunt assesses hemisphere activity using a technique called a line bisection test. This simply involves participants being shown a straight line and being asked to mark where they believe the middle of the line is. It is known a bisection too far to the left indicates the left hemisphere is active in the participant and a bisection too far to the right indicates the right hemisphere is active.

Ms Hunt hopes that participants who are found to have a more active right hemisphere will have eaten more M & Ms than participants who are found to have a more active left hemisphere.

If an active right hemisphere is found to cause people to eat more, then this finding could be used to devise a weight loss strategy. Teaching people who are right hemisphere dominant to think less about promotion and gains, could lead to a change in their thinking and thus reduce their risk of overeating in the future.

Ms Hunt expects to complete her study in the next couple of months. If all goes according to plan, she hopes to conduct a similar study in a clinical setting, testing her theory on people with obesity.

Richard Temperly