Foods high in fat and carbohydrates particularly strongly stimulate the brain's reward center, which can lead to overeating on unhealthy foods such as chips or cream cakes, new research has found.
"Probably under the influence of mother's milk, we respond strongly to foods rich in carbohydrates and fats and find them particularly satisfying because they are essential for survival," explains Mark Tietgemeier from the Max Planck Institute for Metabolic Research in Cologne, who conducted the research in collaboration with the American University Yale.
Except for mother's milk, there is no food in nature that is simultaneously so rich in fats and carbohydrates, scientists note.
The team of experts showed that both fatty foods and foods rich in carbohydrates activate the release of dopamine, responsible for the feeling of satisfaction, in the brain, although in different ways. The combination of fat and carbohydrates enhances this satiety effect by suppressing the feeling of satiety.
"It's the reason we don't stop eating, even when we're full," Titgemeier says.
To examine preferences for different types of food, scientists pitted 40 volunteers against computers, and the reward in the game was food. The food offered in the computer game was either high in fat (cheese) or high in carbohydrates (bakery), or both.
In order to get to certain food, the subjects had to compete with the computer. The scientists found that subjects competed much more for foods that were high in both fat and carbohydrates.
During the game, scientists monitored the brain activity of the volunteers using magnetic resonance imaging. The readings obtained were consistent with the results of the game: the area of the brain where the reward center was most strongly stimulated by foods that were high in both fat and carbohydrates.
The research results were published in the journal Cell Metabolism.
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