"The interesting thing about this finding is that if the same thing happens in humans, eating junk food may change our responses to signals associated with food rewards," says University of New South Wales professor Margaret Morris. "It's like you've just had ice cream for lunch, yet you still go and eat more when you hear the ice cream van come by."
In a study that illustrates how over-indulgence deteriorates self-control and ultimately leads to poor health, researchers conducted a Pavlovian-style experiment on rats.
Working with young male rats, they taught them to associate one of two different sound cues with either cherry- or grape-flavored sugar water, respectively.
Rats maintaining a healthy diet stopped responding to the sound cue after having over-indulged in the flavor with which it was associated, reflecting a mechanism that occurs naturally in most animals to promote proper eating habits.
Next, the rats were allowed to access pie, dumplings, cookies and cake for two weeks, adding an estimated 150 percent more calories to their diet.
A ten percent weight gain and behavior change followed, marked by a lack of interest in novelty foods and continuous response to the sound cue despite over-indulgence in the flavor it was advertising.
Remarking that it took the rats a long time to regain their natural responses after returning to a healthy diet, researchers believe junk food's powerful impact on decision-making could result in long-term changes to the reward circuit area of the brain.
Because human brain chemistry is similarly wired to that of rats, researchers say their study provides increased evidence of advertising's contributions to the obesity crisis.
"As the global obesity epidemic intensifies, advertisements may have a greater effect on people who are overweight and make snacks like chocolate bars harder to resist," says Dr. Amy Reichelt, lead author of the paper and UNSW postdoctoral associate.Read more here:www.sheindress.co.uk/pink-prom-dresses
