Fast Food Fever? Those Cravings Could Be in Your Genes

When you find yourself facing a sudden craving for a double-burger and fries, there may be more behind the insatiable hunger than you realize – it could be in your genes.

Researchers from the University of Cambridge found a link between a person’s preference for fatty food and a genetic variant involving a specific gene known as MC4R.

In layman’s terms, that means some people are simply hardwired with an appetite for high-fat foods, according to the study appearing in the journal Nature Communications.

The researchers gave study participants the option to eat one of three servings of chicken korma, which is a popular curry dish, after tasting all three of them. What the hungry study participants didn’t know was that the researchers toyed with the levels of fat in each dish by adding rapeseed oil to add fat without changing each dish’s taste and texture.

Those with a defective MC4R gene opted for the high-fat version of the chicken korma dish far more often than those without the genetic defect. In fact, study participants with the MC4R variant ate 95% more high-fat chicken korma than lean individuals without the varant.

“Our work shows that even if you tightly control the appearance and taste of food, our brains can detect the nutrient content,” said Professor Sadaf Farooqi from the Wellcome Trust–Medical Research Council Institute of Metabolic Science at the University of Cambridge in a statement.

“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,” added Farooqi.

The researchers estimate that about one in 100 obese individuals have a defective MC4R gene, which can lead to weight gain and the associated dangers, such as cardiovascular disease and diabetes, that come with it. The new study adds to the growing body of literature tying specific genes to obesity.

While more investigation is needed to determine the various reasons that genes might be associated with our food preferences, researchers say that some people’s innate preference for high-fat foods may have an evolutionary basis.

“When there is not much food around, we need energy that can be stored and accessed when needed: fat delivers twice as many calories per gram as carbohydrates or protein and can be readily stored in our bodies,” said Farooqi. Indulging on foods that have a high-fat content “would be a very useful way of defending against starvation.”

The study also found that those who preferred high-fat foods had an opposite reaction to sugary foods – that is, they rejected sugary foods more often than usual. Researchers speculate that people with a preference for fatty foods disregard sugar-laden items because “we can only store [sugar] to a limited extent in the body,” noted Farooqi. In other words, sugar does not fit the long-term plan to stave off starvation.

Individuals with a defective MC4R gene at “significantly less” of the dessert option, a classic English (and delicious-looking) Eton mess, than those with a normal MC4R gene.