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Reward systems in the brain: That's why we can hardly say no to cakes, chips and the like


Why we can't keep our hands off of foods high in fat and carbohydrates

Everyone actually knows that you shouldn't eat too many chips, as they are known as fattening foods. Cream cakes and chocolate bars are also not really healthy foods. Nevertheless, we can hardly say no to such dishes. Researchers have now found out why this is so: Eating high in fat and carbohydrates activates certain areas of the brain particularly strongly.

Sweet and hearty snacks are particularly popular

Delicious chocolates, a piece of cream cake or a candy bar: for many people, craving for sweets is just a matter of thinking about the various delicacies. Others prefer salted snacks such as chips or fries. Excuses for feasting can usually be found quickly: stress in the job, a small reward for getting things done or socializing. Researchers are now giving people who cannot keep their hands off the unhealthy foods yet another excuse: the urge to eat high-fat and high-carbohydrates is influenced by the brain's reward system.

Hardly anyone can stay away from unhealthy food

Although everyone knows that french fries, cream cakes, chips, candy bars and the like make you fat and unhealthy, we cannot stay away from it.

Scientists from the Max Planck Institute (MPI) for Metabolism Research in Cologne have now provided an explanation for this.

As the researchers report, foods that are high in both fat and carbohydrates have a particularly strong impact on the reward system in our brains.

Except breast milk

According to the experts, both fatty and high-carbohydrate foods activate the brain's reward system, albeit via different signaling pathways. When carbohydrates and fats come together in food, this effect is intensified.

In nature there are no foods that combine a high proportion of fats and carbohydrates: Either they are rich in fats like nuts or, like potatoes or cereals, they are rich in carbohydrates.

Breast milk is an exception. "All mammals know breast milk," explains research group leader Marc Tittgemeyer from the Max Planck Institute for Metabolism Research, who conducted the study in cooperation with researchers from Yale University in Connecticut (USA).

"We are likely to be influenced by breast milk to react particularly intensively to foods rich in carbohydrates and fats and to perceive them as particularly rewarding because this is essential for survival."

Game for food

The researchers wanted to know whether people more or less prefer food made from different calorie sources. To answer this question, 40 volunteers played against a computer for food.

Foods that were high in fat or carbohydrates and foods that were both high in fat and high in carbohydrates were offered. In order to acquire food, the test subjects had to outbid the computer.

The willingness to pay was examined. Most money was offered for the fat and carbohydrate-rich food. So it was obviously the most attractive for the study participants.

While playing, the researchers recorded the subjects' brain activity in a magnetic resonance tomograph.

The measurements showed that a combination of fats and carbohydrates activated the brain areas of the reward system more intensively than the other foods offered. This finding agrees with the results of the game.

Reward is stronger than feeling full

A reward stimulus that has contributed to human survival in evolution is doomed to us in today's world of abundance.

"We are not made to say no all the time. That's why we usually don't stop eating even though we're full, ”emphasizes Tittgemeyer. Apparently the reward signals overlay the feeling of satiety - over-saturation and being overweight are the consequences.

In addition, we can hardly estimate the nutritional values ​​of high-fat and high-carbohydrate food: If the researchers asked the study participants to estimate the calorie content of the foods offered, they succeeded relatively accurately in eating high-fat or high-carbohydrates.

However, they were often wrong when it came to eating foods rich in fat and carbohydrates. Food that is high in fats and carbohydrates at the same time does not automatically provide more calories.

The results of the study were published in the journal "Cell Metabolism".

According to the experts, the findings could play an important role in the treatment of people who are overweight. Especially when food becomes an addiction factor, the treatment of consumer behavior is of great importance and a fundamental step out of addiction. (ad)

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Video: Cravings: Its All In Your Head (August 2020).