A study has found a previously unknown mechanism in our brains gets to work when we look at a menu, meaning it could affect the food choices we make. We've all had times when we’re out at a swanky restaurant with the other half, or enjoying a girly lunch with friends, and scan the menu mentally ticking off what the least calorific food is. But there are also times when you don't think about the weight implications and just go for whatever you fancy.
'We found that brain activity tracked the true caloric content of foods'
Scientists at the Montreal Neurological Institute and Hospital have now found the brain works out the calorific density of each dish. This is because people have an awareness of how many calories certain foods contain, which in turn influences the brain.
"Earlier studies found that children and adults tend to choose high-calorie food," study author Alain Dagher, a neurologist, said. "The easy availability and low cost of high-calorie food has been blamed for the rise in obesity.
"Their consumption is largely governed by the anticipated effects of these foods, which are likely learned through experience.
"Our study sought to determine how people's awareness of caloric content influenced the brain areas known to be implicated in evaluating food options.
"We found that brain activity tracked the true caloric content of foods."
The study's findings are published in Psychological Science, a journal of the Association for Psychological Science.
Researchers used 29 healthy participants and monitored how they examined pictures of 50 familiar foods. On a scale from 1 to 20, they were asked to rate how much they liked each food and to estimate how many calories were in them.
While the study group weren't very good at accurately guessing how many calories they contained, the results correlated with how they bid in a simulated auction - where the amount participants were willing to bid on the food matched up with the foods that actually had higher caloric content.
Functional brain scans took place while participants looked at the food photos and showed activity in the ventromedial prefrontal cortex, an area known to encode the value of stimuli and predict immediate consumption, was also correlated with the foods' true caloric content.
Knowing the reasons behind people's food choices can help to control factors that lead to obesity, says Alain.
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