Gene mutations are causing hunger for fatty foods

Mutation of MCR4 leaves sufferers eat more fet, but less sugar
Is there really a gene mutation that increases the appetite for fatty foods? Researchers now found just such a mutation. However, those affected seem to consume less sugary foods at the same time.

The scientists from the internationally recognized University of Cambridge in the UK found that a rare gene mutation has a massive impact on our diet. People with such a gene mutation eat much more fatty foods. The physicians published the results of their study in the journal "Nature Communications".

Does a gene defect affect the consumption of fatty foods? Physicians have found that a gene mutation in the melanocortin-4 receptor really encourages those affected to eat more high-fat foods. (Image: paul_brighton / fotolia.com)

Doctors are studying the eating habits of people with gene mutation
For their study, the scientists tested the eating habits of volunteers at a so-called all-you-can-eat buffet. It quickly became clear that people with a certain gene mutation eat more fatty foods, say the authors. Of course, many people often enjoy fatty foods. But there is a mutation of the so-called melanocortin-4 receptor (MCR4), which leads to an additionally increased consumption of fatty foods. This happens even if the fat content of the food is completely hidden, the doctors add.

Our brain can recognize the nutrient content of food without prior knowledge
If we can accurately control the look and taste of food, our brains can gauge their nutritional value, says author Sadaf Farooqi of the University of Cambridge in a press release. For their small study, the researchers recruited 54 subjects. These then took part in an Indian chicken curry (Chicken Korma). Of the participants, 20 were lean, 20 of the subjects were obese with no MCR4 gene mutation and 14 were obese with a corresponding mutation.

Defect affects the saturation signals in our brain
According to the researchers, about one in every 100 obese people suffers from the gene mutation. This defect of the MC4R gene often affects the weight of those affected. The defect causes saturation signals in the brain can not be properly processed, explain the authors.

Subjects must perform taste test
The test offered each participant a taste test of three different chicken dishes. The three courts were previously manipulated to look the same and taste the same, explain the experts. In reality, it was a low-fat, medium-greasy and high-fat version of the same dish. The fat content of the dishes delivered 20 percent, 40 percent or 60 percent of the calories.

MC4R gene mutation allows subjects to consume more high-fat foods
After tasting, all participants were free to serve themselves and eat as much as they wanted. Each group consumed about the same amount of food, the researchers say. However, participants with an MC4R gene mutation consumed almost twice as much of the high-fat dish compared to the lean participants. 65 percent also ate more from the court than the obese group.

Second test tests the effects on the consumption of sugar
In a second experiment, all participants in the three groups had to choose between three different desserts. All desserts were identical in appearance but contained a different sugar content.

Mutation affects the appetite for carbohydrates and fats
The slender and obese participants preferred the dessert with the highest sugar content. The MC4R group consumed less of all desserts compared to the lean and the other obese participants. The scientists already knew that such a gene mutation is more likely to lead to obesity. However, this study revealed for the first time that the mutation specifically affects the appetite of carbohydrates and fat.

MCR4 defect is a useful survival mechanism from ancient times?
Today, the MCR4 defect is a rather useless (and harmful) mutation for us humans, explain the authors. In our primitive past, this gene mutation could have been the driver for a search for high-fat foods. This would have been a very useful survival mechanism at the time, the researchers say.

Fat provides many calories and is easy to store
If there is little food, we need to be able to store energy when needed. Fat provides twice as many calories per gram as carbohydrates or protein and can easily be stored in our body, says Farooqi. While the study was small in size, if the results can be replicated in larger scale research we hope to better understand the causes of obesity, the researchers concluded. (As)