Being hungry is one of the strongest urges you can feel. If you’re really hungry, it’s just about all you can think about. You see visions of sugar plums dance through your head, every smell is a sensory trigger, and the thought of sitting down with a knife and fork seems like an oasis in a desert. Sometimes when I’ve been so hungry and then I finally get to eat, it doesn’t even hit the spot. If you go past the point of crashing, there is no going back. 
But lots of other sensations and emotions can sometimes masquerade as hunger. Maybe you’re feeling under-stimulated so you reach for the fridge. Maybe you’re feeling anxious so you munch on some chips to drown out the voices. Maybe you’re so angry that all you can do is eat a piece of grocery store birthday cake. This is a different kind of emotional hunger for which food can be a proxy.