I think it depends on the person. I'm vegetarian (no eggs, very little dairy) and don't eat any more than meat eaters do as far as I know. Just the normal light breakfast, snack at lunchtime, and dinner.
I guess so. If I eat a meal that is mostly carbs, my stomach feels full very quickly and I can only eat a small portion, but then an hour or later I'm starving and I have to make myself something to eat again.
So, I can have a chicken curry for example, which is mostly rice, and I won't be able to finish it because I will feel all full and bloated from the rice. Then an hour later I will have to make myself somethig else to eat. Or I can have chicken breast, with some veggies on the side, not feel bloated, but also not be hungry again for hours.
Protein takes longer to digest than carbs.
By protein I don't only mean animal protein.