Obesity Gene Linked with Hunger Hormone

This Chicago Tribune article entitled "Researchers link 'obesity gene' to hunger hormone" examines recent research finding that individuals who have a high-risk version of the FTO gene also have higher levels of the hormone ghrelin, which is an appetite-stimulating hormone, in their bloodstream. Researchers are not sure of the exact link, but believe it may by why some individuals are at much higher risk for obesity than others. Could manipulation of these genes or hormones influence obesity and if so, how much? How much is epigenetics involved in this kind of hormone/gene combination?