How your favourite snacks change your brain to make you pile on weight
JUNK food rewires our brain to keep us coming back for more, a study shows.
Fat and sugar in chocolate bars, crisps and sweets triggers the body’s reward system, teaching it to prefer them to other foods.
German researchers tracked brain activity in two groups of volunteers given yoghurts, with one given a version with higher fat and sugar.
After eight weeks, the part of their brains responsible for motivation was more fired up when given the snack compared to the group given the lower fat alternative.
Dr Marc Tittgemeyer, of the Max Planck Institute for Metabolism Research in Cologne, said junk food forms “new connections” in the brain that are difficult to unlearn.
He said: “Our measurements of brain activity showed that the brain rewires itself through the consumption of fatty foods.
“It subconsciously learns to prefer rewarding food.
“Through these changes in the brain, we will unconsciously always prefer foods that contain a lot of fat and sugar.”
Previous studies in mice showed these brain alterations also caused withdrawal when high fat foods were taken away from them, increasing levels of anxiety.
Regularly eating high fat foods can increase your risk of obesity, as well as deadly heart disease and stroke.
Around a quarter of adults in England are obese, with a further 38 per cent classed as overweight.
The latest research, published in Cell Metabolism, looked at how eating the foods affected what 49 healthy adults preferred later on.
They were given the yoghurts — which had similar levels of calories — twice a day.
Their brains were scanned with a functional MRI while drinking milkshakes at the end of the study.
The group given the higher fat yoghurts responded more strongly to the milkshakes, suggesting their brains had changed, the researchers said.
Dr Tittgemeyer said: “New connections are made in the brain, and they don’t dissolve so quickly.
“After all, the whole point of learning is that once you learn something, you don’t forget it so quickly.”