People ‘genetically wired’ to desire fatty foods
Some people are biologically conditioned to prefer the taste of fatty foods, according to U.K. researchers at the University of Cambridge.
The researchers found that people with the MC4R gene – which is already linked to obesity - showed a preference for high-fat food and ate more of it.
Around one in every 1,000 people carries a defective version of the MC4R gene which controls hunger and appetite as well as how well we burn off calories. So far scientists have discovered that mutations in the gene are the most common genetic cause of severe obesity within families, as having a defect in the MC4R gene means hunger can become insatiable.
In the study, published in the journal Nature Communications, the researchers created a test menu that varied only in fat or sugar content. A test group of 54 volunteers were offered unlimited portions of chicken korma, followed by an Eton mess-style dessert. Some of the meals were loaded with fat while others were lower fat versions.
The volunteers were offered a small sample of each and left to eat as much as they liked of the three dishes. For the pudding researchers varied the sugar content rather than the fat.
In total 14 people with defective MC4R unwittingly ate significantly more of the high-fat korma than the 20 lean individuals and the 20 obese people in the study who were included for comparison.
When it came to dessert, only the MC4R carriers disliked the high-sugar option. Lead researcher Professor Sadaf Farooqi, from the Wellcome Trust Medical Research Council Institute of Metabolic Science at the University of Cambridge, said this suggests our food preferences are in part down to biology.
"Even if you tightly control the appearance and taste of food, our brains can detect the nutrient content,” she said.
"Most of the time we eat foods that are both high in fat and high in sugar. By carefully testing these nutrients separately in this study, and by testing a relatively rare group of people with the defective MC4R gene, we were able to show that specific brain pathways can modulate food preference."
Those carrying the MC4R value fat, which can readily be stored in our bodies, over sugar, which makes sense if the aim is to build up fat stores for energy, adds Prof Farooqi: "Having a pathway that tells you to eat more fat at the expense of sugar, which we can only store to a limited extent in the body, would be a very useful way of defending against starvation."