High fat and high sugar foods change the brain so that it ‘learns’ to prefer these types of food, a new study has shown.

Researchers found that the brain ‘re-wires’ itself if high-fat foods are consumed regularly – even if it is a small amount – so we then unconsciously favour this sort of food.

To try to understand more about why we like treat food so much, a team from the Max Planck Institute for Metabolism Research in Germany and Yale University set out to test one hypothesis.

Lead author Sharmili Edwin Thanarajah said: “Our tendency to eat high-fat and high-sugar foods, the so-called Western diet, could be innate or develop as a result of being overweight. But we think that the brain learns this preference.”

Their study involved two groups of volunteers, with one group having a high fat, high sugar pudding every day for eight weeks alongside their usual diet.

The other group ate a pudding with the same calorie content but less fat.

The participants’ brain activity was examined before and during the study period, with researchers noting that the brain’s response increased significantly in the group which consumed the high fat, high fat pudding. In particular, this was seen in the part of the brain responsible for reward and motivation.

Marc Tittgemeyer, who led the study, said: “Our measurements of brain activity showed that the brain rewires itself through the consumption of chips and co. It subconsciously learns to prefer rewarding food. Through these changes in the brain, we will unconsciously always prefer the foods that contain a lot of fat and sugar.”

While the test participants’ weight or blood sugar levels did not alter any more than the control group’s, the researchers noted that preference for this type of food will remain following the culmination of the study, saying: “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.”

Read the study in Cell Metabolism.

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