Shine OnScientists discover how ‘obesity gene’ makes people fat
The worldwide obesity epidemic and its rapidly rising number of victims has international medical researchers scrambling for answers.
A recent study, publish Monday in the Journal of Clinical Investigation, now sheds light on why some overweight people are more likely to become obese.
A common variation in the FTO gene, also known as the "obesity gene," affects one in six people, making them 70 per cent more likely to become obese.
While researchers first discovered FTO's role in obesity in 2007, they never figured why having this gene variant made people more susceptible to being obese - until now.
Researchers from University College London, the Medical Research Council and King’s College London Institute of Psychiatry have discovered that people with this gene variant also have higher levels of the hunger hormone, ghrelin, which makes them feel hungry just after eating.
"We could see their hunger wasn't suppressing properly," lead researcher, Dr. Rachel Batterham from University College London, tells WebMD.
Also see: Tips and tricks to help prevent overeating
"Their brain is set up to be particularly interested in anything to do with high-calorie food," she tells BBC.
Her trial involved 20 healthy weight male participants, 10 who had the FTO gene variant and 10 who didn't. Even within this normal weight range group, men with the FTO gene variant had more body fat.
Researchers put the men through two tests after eating a meal, one which involved asking them questions about their appetite, and the other which involved doing a blood test to check for ghrelin hormone levels.
They also scanned their brains after looking at images of food and found that participants with the FTO gene variant reacted differently.
"The areas of the brain that respond differently are the reward, appetite, motivation, visual interest areas," Dr. Batterham tells WebMD.
Also see: 'Healthy' foods that are actually making you fat
Previous research has shown that ghrelin can be reduced by eating a high-protein diet.
"We know that protein is the best nutrient at suppressing ghrelin," says Dr. Batterham
Also, certain types of exercise are better at lowering ghrelin.
"Aerobic exercise lowers ghrelin, but weight-lifting doesn't," she says.
Dr. Batterham suggests that genetic testing, as well as obesity drugs, could become a routine part of managing obesity.
Two new experimental obesity drugs are known to suppress ghrelin and could be particularly effective if targeted at patients with the at-risk variant of the gene.
Vivus Inc's Qsymia and Arena Pharmaceuticals Inc's Belviq were approved by the U.S. Food and Drug Administration last year.
Dr. Batterham's study was funded by the MRC, Rosetrees Trust, the National Institute for Health Research University College London Hospitals Biomedical Research Centre (NIHR BRC) and the Wellcome Trust.
