Nutritional science | A fatty delicacy is more addictive than a light one – it feels better in the mouth and in the brain

Fleshy fat yogurt or ice cream beats a lighter alternative in many people’s opinion, and it’s not just because of the taste. The high-fat product is also addictive with its mouthfeel.

Brain researcher at Oxford University Fabian Grabenhorst and his colleagues noticed in his researchthat the brain area connected to sensations and the attractiveness of food in the front part of the frontal lobe – the so-called orbitofrontal cortex – gets excited by the recognition of fatty food.

Fat increases the viscosity of liquid food. However, the researchers were now more interested in the melting oiliness of the food, which reduces friction as the food slides against the tongue and the walls of the mouth.

Let’s try for this, the researchers prepared vanilla-flavored milkshakes with varying fat and sugar content.

In one option, instead of fat, they added a thickener used by the food industry to give juiciness.

In addition, the researchers procured pig tongues from a local butcher. With these, they measured the sliding friction of their milkshakes with different compositions in conditions reminiscent of the human mouth. The friction really decreased according to the fat content of the shake.

Next, more than twenty test subjects got to slurp milkshakes. After tasting, they were asked to say how much they were willing to pay to get more milkshakes.

Willingness to pay told the researchers how much the participants liked each vanilla drink.

During the tasting, the subjects’ brains were imaged with a functional magnetic resonance imaging device.

It turned out that the differences in the composition of the shakes and their pleasantness to the test subjects were reflected in the reactions of the orbitofrontal cortex. The preference was partly explained by the mouth feel associated with the sliding friction.

Mouthfeel also affects people’s food choices. It was confirmed when the test subjects could taste three curries with different fat content and choose their favorite for lunch.

This part of the experiment was done so that the subjects did not know that the researchers were observing their choices.

Fatty meals were piled on their plates, especially by those whose orbitofrontal cortex had reacted particularly strongly to the greasy mouthfeel in the shake experiment.

Grabenhorst told to Nature magazine that their findings may help develop low-calorie foods. The study itself was published by The Journal of Neuroscience.

Published in Tiede magazine 13/2023.