Some people's preference for high-calorie foods may be influenced by the presence of certain genetic variants, according to researchers.
Study leader Dr. Tony Goldstone, from Imperial College London in the UK, and colleagues have identified two genetic variants that influence whether we opt for high-calorie or low-calorie foods - a finding they say could open the door to more personalized treatment options for obesity.
The team recently presented their findings at The Obesity Society Annual Meeting in Los Angeles, CA.
Diets high in fat and sugar are a major cause of obesity; when we consume more calories than we burn, this can lead to weight gain. As such, a healthy, balanced diet - alongside physical activity - is deemed the best strategy for weight loss; but for some people, sticking to a healthy diet is easier said than done.
For their study, Dr. Goldstone and colleagues set out to determine whether a person's food choices may be influenced by certain genetic variants.
The team conducted DNA genotyping on 45 white European adults aged 19-55 years to identify the presence of variants near two genes: the FTO gene, which has been associated with obesity predisposition, and the DRD2 gene, which plays a role in the regulation of dopamine in the brain - a neurotransmitter involved in rewards and cravings.
Participants had a body mass index (BMI) ranging from 19.1 kg/m2 to 53.1 kg/m2, representing weights ranging from healthy to obese.
Subjects were asked to view pictures of high- and low-calorie foods and rate how appealing they were, while the researchers used functional magnetic resonance imaging (fMRI) to analyze their brain activity.
FTO gene variant influences brain's reward system
The researchers found that the participants who possessed a variant near the FTO gene and who rated the high-calorie foods as more appealing demonstrated greater activity in a part of the brain called the orbitofrontal cortex.
What is more, the researchers say that - for the first time - they found participants who had a variant near the FTO gene and who preferred the high-calorie foods showed greater activity in a part of the brain known as the striatum, though they note this activity was dependent on which DRD2 gene variant they possessed.
Based on their findings, the researchers suggest that individuals who possess the FTO gene may be at greater risk for obesity early because dopamine signals trigger a sense of craving and reward in the presence of unhealthy foods.
"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.
Potential for individualized obesity treatments
The team says their findings indicate people with the FTO and DRD2 gene variants may benefit from more personalized treatments for obesity.
One treatment, they suggest, could involve using gut hormones that target dopamine cells in the brain to alter the hormone's influence on cravings for high-calorie foods.
Commenting on the study results, Leah Wingham, PhD, fellow of The Obesity Society and executive director of Paso Del Norte Institute for Healthy Living in El Paso, TX, says:
"These findings help us better understand the biological basis of behaviors that may predispose some people to overeating high-calorie foods, and hence obesity.
It could help us better target treatments for obesity so particular people get the most effective treatment, as individualized approaches to obesity are necessary."
Medical News Today recently reported on a study suggesting that injecting a gene into the brain that codes for leptin - an appetite-suppressing hormone - may be more effective than dieting for weight loss.