Why the brain likes fatty foods so much: They really are a form of reward

Why the brain likes fatty foods so much: They really are a form of reward

OfAnna Fregonara

A study has discovered that they are able to activate a precise area of ​​the brain, involved in the “reward” mechanisms selected by evolution. Some people are more “vulnerable”

The brain tricks our stomach and makes us choose the fat food. Why? They are very tasty foods, think of ice cream, and also their consistency, soft and smooth, makes us appreciate them from the moment we put them in our mouths.

Where predilection originates

But a group of scholars went further and identified an area of ​​the brain which seems to “light up” when it “feels” the velvety consistency of fatty foods, a sort of appreciation for what we are eating and which could guide us in our eating habits. On the other hand, sugars and fats have always increased the reward value of foodsbut they also contribute to overeating andobesity.

The experiment

For this reason the results of the study, published in the scientific journal The Journal of Neurosciencethey could also partly help to formulate solutions targeted to try to counteract weight gain.
The researchers have prepared some smoothies, with different amounts of fat and sugar, and they placed a sample between two pig tongues (recovered from a local butcher) to measure the degree of friction and obtain a numerical softness index for each: a way to quantify the mouthfeel of foods. Then they asked 22 volunteers, also subjecting them to brain MRI, to taste the same types of smoothies. After the tastings, participants said how much they would pay to consume an entire glass of the preparation, a way to gauge appreciation.

The results

By analyzing brain scans, we saw how the responses of orbitofrontal cortex (Ofc), a specific area of ​​our reward system, varied with each taste, reflecting the different smooth, oily texture produced by fatty liquids on the surfaces of the mouth. These different brain activities also reflected the amounts the subjects said they were willing to pay for a whole milkshake. Furthermore, the neural sensitivity of the Ofc to fatty texture predicted individuals’ preferences in a test in which the same volunteers were invited to eat an unrestricted lunch of curry foods with different amounts of fat and sugar. Subjects whose Ofc were more sensitive to fat ate a greater amount of foods that contained more.
This, according to scholars, suggests that the mechanical parameter of the friction of fats against the surfaces of the mouth influences the brain’s reward systems, directing our food choices and exposing us more to the risk of overeating.

Some more “sensitive” people

«The study is of great relevance from a methodological and theoretical point of view. Scientists have found an innovative way to quantify the mouthfeel of fatty foods, given the neural correspondence between the more texture-sensitive Ofc and the amount of fatty foods ingested. This measurement could represent a marker to predict the future diet of high-risk subjectsfor example, insulin resistance, diabetes and obesity”, comments Carol Coricelli, researcher in the department of Neuroscience and Nutrition at the German Institute of Human Nutrition of Potsdam-Rebrücke. «The preference for fat and sugar has evolutionary roots. In the past, when food sources were scarce, the ability to quickly and efficiently obtain energy from foods high in fat and sugar was advantageous for survival and reproduction,” continues Coricelli. «This “adaptive” behavior has been preserved, but the surrounding environment has changed drastically and today we can define it as obesogenic: the presence of an abundance of food favors, in fact, obesity which is constantly growing».

The reward drives the choice

“Furthermore, sugar provides quick energy and easily accessible. Our brain, which consumes a significant amount of the body’s energy, is naturally inclined to seek out these energy-dense substances. This aspect, combined with the pleasant sensory experience of consuming fatty foods, makes our reward system highly sensitive to these high-calorie foods. The neural circuits of reward they guide our preferences at the table by assigning greater value to these foods, which will be chosen when compared with other stimuli with less reward such as bitter foods and those with low calorie content.”

The reward system

The human reward system encourages actions beneficial to the individual and the species, regulates motivation, learning and pleasure. «Pleasure and desire, among the rewarding properties of food, deserve a distinction. The first is triggered when the neurotransmitter dopamine, and the dopaminergic circuits make us always return to seeking positive experiences. The brain registers this association and we are motivated to repeat that behavior”, says neuroscientist Coricelli. «The second arises when we feel the desire for one reward. This mechanism also underlies the development of habitssuch as that of associating an experience with the consumption of a certain food, think of popcorn at the cinema. Repeated habits in some cases can lead to addictionseven in the case of food: in particular fatty and caloric foods overexcite the reward system.”

March 10, 2024


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