Brain gets 'high' from junk food

The same brain pathways that make people addicted to drugs also addict them to high calorie foods, according to a recent US study.

The research adds credence to some scientists' belief that addiction to pleasure comes from over-stimulation, and that there may be a neurological way to treat overeating.

For the study, scientists fed high-calorie food such as bacon, sausages, and cheesecake to rats.

After the rats had gained a lot of weight from eating such high-fat food, scientists compared them to rats raised on a well-balanced diet.

The rats fed junk food ate twice as many calories, on average, as the second set of rats.

Paul Kenny, an associate professor at the Scripps Research Institute in Florida, said that when he and his colleagues removed junk food from the rats' diets, the rats refused to eat at all.

He said that they changed their diet preference so greatly that they basically starved themselves for two weeks after being forced to eat mainly vegetables and low-fat foods.

The researchers also used electric shock in order to prevent the rats from overeating.

However, the rats ignored the electric shocks and continued to eat.

After the researchers felt they had definitely established that the rats were addicted to pleasure, they attempted to find a neurological basis for the addiction itself.

Kenny and another student focused on the neurotransmitter dopamine, which is released during sex, eating, and drug use.

Other studies had shown that cocaine users have decreased levels of dopamine in their brains, after they have used the drug.

In cocaine users, once dopamine flooding has caused over-stimulation, the appropriate brain receptors require more cocaine than before in order to establish the same level of flooding as before.

People consequently become addicted to cocaine, because in order to establish the same level of flooding as before they must take it in increasingly larger amounts, and more and more often.

For the present study, the researchers found that the food-addicted mice had gone through the same kind of neurological transformation.

Kenny said that his team's findings confirmed what they and many others had always suspected, that the mechanism of addiction drove the development of compulsive eating.