This is a big problem for me and SO annoying! Previously I used to be really interested in eating and in fact, ate enough to be uncomfortably overweight. It's only been since I have had a brain injury (several years now), which because of its location, tends to accentuate my (undiagnosed) autistic tendencies.
It's like I don't recognize the signs of hunger, and sometimes even when I know I'm hungry it's difficult to make myself eat. My diet is very restricted due to sensory issues, and if I don't have exactly the right food(s) it's super difficult for me to make myself eat. As a result (perhaps) my diet is unbalanced, but I've come to see it as "some calories are better than no calories" so if it's an emergency I'll go ahead and eat [x high-calorie food] even though it's not nutritionally ideal.
It's a huge struggle to maintain any sort of routine or schedule since I haven't been able to work the last several years and spend most days just kicking back at my house. But, having a routine is one of my goals, so I hope to get that together some day. Been trying to eat whenever my pets do, at least... the cats in particular don't let me get away with forgetting to feed them. The dog, I'm afraid, is too polite to ask for anything to eat, but the only way to feed the cats peacefully is by feeding the dog first, or she will lunge at them trying to start up a fight. So she does get fed. As I said, I'm trying to attach my own consumption to the pets' meals, but I don't always remember and sometimes I rebel against myself even if I do remember.