I starved myself when I was young, going through cycles of limiting myself to 400 calories a day or only eating one meal every three days, then going as long as ten days without eating anything at all on occasions.

I'm over that (or as much so as anyone who has survived an eating disorder ever really gets over it, anyway - I'll never have a comfortable relationship with food) but my digestive system isn't and probably never will be: I can only manage one meal a day and just don't get hungry so, if I'm too tired and forget to eat, I'll go 48 hours without even realising.