Is 'Sweet Tooth' Genetic? Here's What This Study Says

Those who constantly crave high-calorie food, feel free to blame your genes.

Lead researcher Dr Tony Goldstone and colleagues have discovered why some people prefer high-calorie while some opt for those with low-calorie content. The researchers from Imperial College London attribute the "craving" (or lack of it) to two genetic variants: the FTO and the DRD2.

Medical News Today reported that before Goldstone and co-authors came up with the finding, they began by genotyping the DNA of 45 Caucasian males aged 19-55 years. The participants had a Body Mass Index(BMI) ranging from 19.1 kg/m2 to 53.1 kg/m2 -- a good representation of normal to obese body weight. The authors had an objective of uncovering "variants" in the FTO gene (a genetic element associated with obesity) and the DDR2 gene (a gene which is responsible for the flow of dopamine in the human brain). The latter gene was identified in the same report as a neurotransmitter which plays a major role in "rewards and cravings."

To test their hypothesis, the researchers presented the subjects with photos of high- and low-calorie foods. They then asked them to "rate how appealing they were," while simultaneously assessing their brain activity using a functional magnetic resonance imaging (fMRI), as per Medical News Today.

Remarkably, the Goldstone and colleagues found that there is a "greater activity" in the orbitofrontal cortex of research subjects who rated the high-calorie foods as more appealing. Moreover, they were also reported to have a variant "near the FTO gene."

The Daily Mail UK furthered that these participants do not have the same level of brain activity when they looked at the pictures of low-calorie foods.

"Interestingly, for the first time we also found that the activation in a part of the brain called the striatum was increased when those with the variant in the FTO looked at high-calorie foods, but this depended on which variant of the other gene DRD2 they possessed," Dr Gladstone noted as per The Daily Mail UK.

Goldstone and co-authors then put forward that the subjects who possess the FTO gene "may be at greater risk for obesity early" because their dopamine levels shoot up when presented with unhealthy food. "It means they may experience more cravings than the average person when presented with high-calorie foods -- that is, those high in fat and/or sugar -- leading them to eat more of these foods," explains Dr. Goldstone, as cited by Medical News Today.

A little more than one in three adults in the US are obese and they are feared to be at increased risk of heart disease, stroke, type 2 diabetes and some forms of cancer, according to the same report.