SCIENCE
09/02/2015 02:56 pm ET Updated Sep 03, 2015

Are Obese People Wired To Crave High-Calorie Foods?

A new study finds food addiction may be hard-wired into the brain.

Scientists and doctors have long debated whether "food addiction" is real and whether it plays a role in obesity. A new brain imaging study offers intriguing evidence that suggests obese people are hard-wired to crave sugary and fatty foods.

 A team of international scientists, who presented their findings at a neuroscience conference in Amsterdam earlier this week, has discovered that food cravings can lead to brain and behavioral changes in obese people similar to those seen in drug addicts.

"What we do know is that both food and drugs can cause behaviors that are very similar to addiction, such as the inability to cut down, continued use despite negative consequences, and a sense of a loss of control," Dr. Oren Contreras-Rodriguez, a researcher at the University of Granada in Spain and one of the study's authors, told The Huffington Post in an email.

"Comparing food addiction with drug addiction is controversial -- drug use changes the way the brain functions, and this is not still clear in obesity," Contreras-Rodriguez added.

But the study did show that food cravings seem to activate the brain's reward system differently in obese people compared to individuals of a healthy weight.

For the study, 39 obese people and 42 healthy-weight people were given a buffet-style meal. A few hours later, their brains were scanned while they viewed photos of high-calorie foods from the buffet, which was meant to stimulate cravings.

What did the brain scans reveal?  

The brains of the healthy-weight people showed increased connectivity between areas involved in flavor evaluation and areas involved in emotion and reward-motivated decision-making.

This means that the people were more likely to consider how good the food tastes, as well as other factors -- like nutrition value and hunger level -- when determining whether or not they wanted to eat it. That resulted in fewer cravings.

The brain imaging of the obese people, on the other hand, showed they associated high-calorie foods (read: sugar and fat) with the promise of reward. Researchers pointed to the increased connectivity between two other areas of the brain -- one that processes reward-motivated behaviors, called the dorsal caudate, and another that assesses food’s energetic value, called the somatosensory cortex.

The association of these two brain networks can make it more difficult for obese people to turn down unhealthy foods, Contreras-Rodriguez said.

When the researchers measured the participants' body mass index three months later, they found that the weight gain in the obese people correlated with the level of connectivity between the dorsal caudate and somatosensory cortex. In other words, cravings seemed to predict weight gain. 

Obesity is one of the most pressing public health issues in the U.S., and these early findings are a promising move towards developing a better understanding of the neurology of the condition.

Eventually, they may point towards treatments that target food cravings, perhaps through the use of drugs or brain stimulation. "The more researchers understand about what triggers obesity, the better they can treat it,” Contreras-Rodriguez said.

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