Is this commonly known as "head hunger" as opposed to real hunger? Because this is something very common when your blood sugar spikes then crashes (from insulin along with the rest of the chemical/hormonal cascade). It feels like desperate hunger, even though your stomach may still be full of food - it can actually be distended because it's so full, and yet your brain is desperately screaming for you to eat again, because what it perceives is the blood sugar drop, the high insulin, and all the hormonal/chemical changes which indicate to your brain that you are extremely depleted, so eating as soon as possible is of the utmost importance.



I suppose you can be conditioned to experience an involuntary pavlovian reaction to almost anything, but I'd be almost willing to bet that the subjects of this study actually just learned to recognize how they felt when their blood sugar reached the level deemed acceptable for them to eat again.