Why do people prefer foods with fats and carbohydrates?
Certain foods, such as fast foods, which combine fats and carbohydrates, have a particularly strong impact on the reward system in our brain. As a result, we eat a lot more, which can lead to obesity and obesity.
In their current study, scientists from the internationally recognized Yale University found that a combination of fats and carbohydrates in food leads to excessive food intake. The doctors published the results of their study in the English-language journal "Cell Metabolism".
Which foods contain many fats and carbohydrates?
In natural form there are actually no foods that combine a high proportion of fats and carbohydrates. Either foods contain a lot of fats, such as nuts, or they contain a lot of carbohydrates, such as potatoes or grains, the experts explain.
The reward system is outwitted by fast food
The brain develops a greater desire for nutritious foods. So-called highly processed foods often consist of carbohydrates that are cooked in fat and coated with sugar or flavored. Such foods confuse the regulatory mechanism and the reward system in our minds. This in turn affects our food intake. Such foods actually have a stronger impact on the brain's reward system, which leads us to choose fast food over healthier snacks, the scientists explain. For example, if you want to eat a banana instead of potato chips in front of the TV, but your brain is more used to fast food, it will prefer the fatty but low-nutrient potato chips.
Subjects had problems with calorie estimates
The fat-carbohydrate combination affects neuronal circuits in the striatum in the prefrontal cortex of the brain more than a sweeter or higher-energy food or a larger portion of food. The participants were very good at estimating how much calories are ingested from fat, but they had problems estimating the amount of very unhealthy calories from carbohydrates, explains study author Dr. Dana Small from Yale University. Food that is rich in fats and carbohydrates at the same time automatically contains more calories.
Assessment of the nutritional value should lead to adaptive decisions
The study shows that when the two nutrients are combined, the brain appears to overestimate the energetic value of the food, the expert adds. If foods contain such a combination, according to Dr. Small manipulated by consuming innate body signals. The biological process that regulates the association of food with its nutritional value has evolved in the course of evolution to accurately estimate the value of a food so that organisms can make adaptive decisions. For example, a mouse for food with little energy shouldn't risk running outdoors and exposing itself to a predator there, the researchers explain.
Over 200 participants were examined for the study
The current study examined more than 200 adult subjects with a normal BMI. Participants underwent a brain scan while being shown photos of popular snacks that contained mostly fat, sugar, or a combination of these. They were given a limited amount of money to offer for the various foods. The subjects offered the most money for the high-fat and high-carbohydrate food. This suggests that this type of food was most attractive to the participants. When measuring brain activity, it was found that a combination of fats and carbohydrates activated the brain areas of the reward system more intensively compared to other foods, the scientists continued.
Improper diet leads to obesity
In nature, foods high in fats and carbohydrates are very rare and tend to contain fiber, which slows down the metabolism, the experts explain. In contrast, processed foods very often have a high fat and carbohydrate content. This was also reflected in the subjects' bids. The so-called reward signals seem to overlay our feeling of satiety, which means that those affected often develop excess weight.
The typical western diet is very unhealthy
A so-called western diet is almost full of fatty and sugary foods such as burgers, french fries and lemonades. The health effects of such a diet range from obesity, high blood pressure and diabetes to heart disease, colon cancer and dementia. (as)