Many people find high-sugar and fattening food irresistible, and scientists have now investigated why this is so.
In a paper in Cell Metabolism, scientists from the Max Planck Institute for Metabolism Research in Cologne, in collaboration with Yale University, have concluded that the brain “learns” this preference for sweets. In other words, if someone regularly eats even a small quantity of sweets, the brain learns to expect such foods in future.
The scientists tested this hypothesis on volunteers. For four weeks, they gave one group a small pudding containing a lot of fat and sugar per day, in addition to their normal diet. To another group of volunteers, they gave a pudding that contained the same number of calories but less fat. The brain activity of both groups was measured throughout the study period.
In the group who ate the high-sugar and high-fat pudding, the brain's response to such foods was greatly increased after eight weeks. This activated a region in the brain called the dopaminergic system. This region processes our understanding of motivation and reward.
“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,” a press release from Max Planck Institute quoted lead researcher Marc Tittgemeyer as saying.
Did the participants in group gain weight compared to those in the other group? Not during the study period, the release said. Their levels of blood sugar or cholesterol did not change either. But the researchers expect that the preference for sugary foods will continue even after the study has ended.
"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," Tittgemeyer was quoted as saying.