When it comes to eating junk food one may blame the brain. Addiction is a disease and the same has been proved by a study.

Two areas of the brain have to work together to give the self-control to reject unhealthy foods. California Institute of Technology researchers used MRI to scan the brains of volunteers as they looked at photos of dozens of types of foods and decided which ones theyd like to eat. They found significant differences in the brain activity between people who had self-control in terms of making food choices and those with no self-control. An area of the brain called the ventromedial prefrontal cortex is involved in all value-based decisions. When ventromedial prefrontal cortex activity decreases, a person will probably reject an item, whereas increased activity means theyll probably choose it.

The study published in the issue of Science found that in people with no self-control, the ventromedial prefrontal cortex seemed to take into consideration only the taste of a food. In people with good self-control another area of the brain called dorsolateral prefrontal cortex becomes active and modulates the basic value signals so that the self-controllers also incorporate health considerations into their decisions.

The study showed that ventromedial prefrontal cortex is active during every decision and that the dorsolateral prefrontal cortex is more active when a person is using self-control.