Sometimes our body systems can get messed up and the signal between our brains and our stomachs don't always connect. So sometimes you could be hungry but ecause your brain didn't get the memo from your stomach - you don't eat. Sometimes it's because we've trained ourselves to not eat much or anything at all, and so we train ourselves to exist off less and less food... and that's not good. So our bodies forget to interpret "hungry" signals.

It is a good idea to eat regularly, even if you're not actually feeling hungry. Small meals and snacks. Stuff that's good for you that may train your body to recognize being hungry again. But it takes time, unfortunately.