Anyone who’s ever struggled with their weight knows all the tricks for taming appetite: don’t eat mindlessly in front of the telly, don’t bolt your food and resist the triggers for non-hungry eating like boredom and stress. But what if you’d acquired a faulty gene that gave you such a powerful appetite that none of these strategies worked?
That’s the problem for three to six per cent of people who become very obese – often the ones who the rest us think need ‘more willpower’. They’re unlucky enough to inherit a defective MC4R gene – and it stops the brain from getting the message that they’ve had enough to eat. “For people with this gene there’s a genuine reason why they overeat – they have an uncontrollable appetite because their brain keeps telling them to eat,” says Dr Daniel Chen from the Diabetes and Obesity Research Program at Sydney’s Garvan Institute of Medical Research. “It’s important to raise the profile of MC4R because people with a defect in this gene can pass it on to their children. But if we can identify a two year old with the gene, for instance, then they may be candidates for more targeted therapy