Is advertising to blame for obesity epidemic The sight of fatty foods triggers hunger, claims study
Simply viewing high calorie food images
activated brain regions that control appetite and reward
16:16 GMT, 26 June 2012
Viewing pictures of high calorie food also significantly increased ratings of hunger and desire for sweet and savoury foods
A picture could be worth a thousand calories after a study revealed images of fatty food can trigger hunger pangs.
The finding could point to one cause of obesity and overeating in western societies.
Scientists have revealed how looking at pictures of high calorie food stimulates the brain’s appetite control centre and results in an increased desire for food.
Having drinks with added sweeteners also activated brain regions involved in hunger and desire – suggesting a possible link to the obesity epidemic.
Using functional magnetic resonance imaging – fMRI – researchers studied the brain responses of 13 obese young Hispanic women, as they are at 'high risk for continued weight gain and obesity', said Dr Kathleen Page.
Each participant had two fMRI scans as they viewed images of high calorie foods, such as ice cream and cupcakes, as well as low calorie foods like fruit and veg, and non-food pics.
After each set of images, participants rated their hunger and desire for either sweet or savoury foods on a scale of one to ten – drinking 50 grams of glucose – the amount in a can of soft drink – on one occasion and fructose on another halfway through the scans, with the two making up table sugar and high-fructose corn syrup.
As fMRI measures blood flow to the brain, regions with increased blood flow indicated greater activity – with researchers measuring which brain regions were activated when viewing images and how sugar intake influenced this.
Results showed simply viewing high calorie food images activated brain regions that control appetite and reward, compared to pictures of non foods.
Viewing pictures of high calorie food also significantly increased ratings of hunger and desire for sweet and savoury foods.
Researchers also found ratings of hunger and desire for savoury food were higher after drinking either sugar beverage – but fructose produced greater activation of brain regions involved in reward and motivation for food.
Dr Page, of the University of Southern California, US, said: 'These findings suggest that added sweeteners could be one of the main contributors to the obesity epidemic.
'This stimulation of the brain’s reward areas may contribute to overeating and obesity.
'We thought this was a striking finding, because the current environment is inundated with advertisements showing images of high-calorie foods.'
The study was presented at The Endocrine Society’s 94th annual meeting in Houston, US.