Snackers are like junkies, says study

People who cannot resist their favourite snacks may have found an excuse in science – humans become addicted to food in the same way they can become hooked on drugs, researchers said today.

Claims that tasty foods, such as chocolate, ice-cream and pizza, are addictive, won backing from researchers in the United States.

They found that the part of the brain which is activated in a craving drug addict, is more active among people anticipating their favourite food.

The addictive nature of food, combined with constant temptation, could explain the current obesity epidemic which is blighting many developed countries, it was claimed.

The researchers, at the Brookhaven National Laboratory, in New York, said their study had “produced new evidence that brain circuits involved in drug addiction are also activated by the desire for food”.

“The mere display of food – smelling and tasting favourite foods without actually eating them – causes increases in metabolism throughout the brain.

“Increases of metabolism in the right orbito-frontal cortex, a brain region that controls drive and pleasure, also correlate strongly with self-reports of desire for food and hunger,” they said in a statement.

Previous experiments at the same government laboratory have found that the same part of the brain is involved in compulsive behaviour characteristics in cocaine addicts.

In earlier studies they also found that the make-up of an obese person’s brain was similar to that of a drug addict.

For the new study, 12 volunteers, with an average age of 28, fasted for nearly a day before being offered their favourite foods.

The food items most frequently chosen were bacon, egg and cheese sandwich, cinnamon bun, pizza, hamburger with cheese, fried chicken, lasagne, barbecue rib, ice cream, brownie and chocolate cake.

Scientists watched how the subjects reacted to the foods by using positron emission tomography (PET), a scanning technique, to measure brain metabolism.

The food was warmed and the subjects were allowed to view and smell it, as well as taste a small portion which was placed on their tongues with a cotton swab.

They were also asked to describe the foods as they tasted them.

The subjects were also asked to describe, on a scale of one to 10, whether they felt hungry at the start of the study and at five-minute intervals for a total of 45 minutes.

Metabolism increased in virtually all areas of the brain by 24%, but the biggest change was noticed in the orbito-frontal cortex.

The study’s lead author, Gene-Jack Wang, said advertisements and the constant exposure people have to food make some of it just too tempting to addicts.

“The high sensitivity of this brain region to food stimuli, coupled with the huge number and variety of these stimuli in the environment, likely contributes to the epidemic of obesity,” he said.

The results of the study appear in the April 2004 issue of the US journal NeuroImage.