I magine you’re in a meeting room when someone brings out the biscuits – a packet of Jammie Dodgers, perhaps, or a nice little plate of custard creams. Maybe you want one and maybe you don’t, but the chances are the people around you are all responding differently: someone will grab a couple straight away, someone else will eat one without seeming to notice, another will barely be aware the biscuits exist, and someone will spend the whole meeting wanting one but not taking it. Our appetites and responses to food vary wildly – but what’s going on behind the scenes to govern them? And has modern food somehow hijacked the process? Grab a biscuit (or don’t) and settle in. “First, it’s important to distinguish between hunger and appetite,” says Giles Yeo, a professor of molecular neuroendocrinology at the University of Cambridge and the author of Why Calories Don’t Count. “Hunger is a feeling – it’s what happens in the run-up to you deciding you need to eat something.…