How 'obesity gene' makes people fat

Researchers have found how a gene linked with obesity makes people fat by making them increasingly hungry.

Individuals carrying the "obesity-risk" allele of the fat mass and obesity associated gene, FTO, are prone to obesity and obesity related eating behaviours such as increased food consumption, preference for high fat foods and lack of satiation after eating. However, how this particular gene regulates obesity prone behaviours is not fully understood.

Rachel Batterham and colleagues at University College London identified a link between FTO and the hunger-stimulating hormone, ghrelin.

Subjects homozygous for the "obesity-risk" allele of FTO had higher concentrations of circulating ghrelin after eating, which correlated with an absence of satiation.

They demonstrate that FTO directly demethylates ghrelin mRNA, altering its production. These studies offer new insight into why individuals that carry the "obesity-risk" allele of the FTO gene are prone to obesity.

The study has been published in the Journal of Clinical Investigation.