Another thing to bear in mind that appetite is a very odd thing. My conclusion through personal experience is that it is a link between mind and body that can be manipulated quite a bit (I think the mind picks up on certain cues from the body that don't mean "I am hungry" but "food has passed a point in the digestive system").
For example, before I figured out how to gain weight within the limitations of my diet, I used to have a 300 calorie breakfast between 7-8AM which I could start to feel peckish at around 10-11-ish. These days I have a 600 calorie breakfast and I see much the same effect on my appetite (my current aim is to maintain weight though I've upped the exercise).
Since finding a diet that works for me, I'm often eating about 1.5x the amount of rice I used to for each meal which I go through phases of feeling like that's too much and at other times is fine.
Also, because of my illness I've sometimes had to fast for medical examinations. When undergoing a hydrogen breath test (testing for lactose intolerance), I had to fast from waking up time for a few hours (IIRC between about 7-11AM), and that morning I didn't even vaguely feel peckish at any point, whereas most mornings if I delayed breakfast by an hour I'd definitely be feeling hungry. I think that morning I had simply made my mind up subconsciously that food wasn't even vaguely on the cards.
Another example is that if I tried to eat minimally in the morning I'd really feel hungry, but after lunch I think I'd be quite happy not to eat again for 8 hours (assuming I haven't been physically exerting myself a lot in that time). At 5-7 ish I eat my evening meal in pretty much any case.