My biggest eating habit change is that I've noticed I can't the same quantity of food that I used to, and I also can't eat junk food like I used to.
I really don't understand it, but I noticed almost immediately that while I used to able to completely stuff myself at buffets, eating 4 full plates sometimes, that number dropped down to 3 mostly-full plates before I was completely stuffed.
The big thing that I have absolutely no explanation for, though, is that for some reason food seems to affect me more. Like, pre-transition I could eat an entire gigantic bag of gummi worms, I actually ate almost two full bags of potato chips in one day before, an entire pizza with almost no trouble, and none of it ever seemed to affect me.
Now, suddenly, I can't really eat potato chips anymore. They make my stomach feel unpleasantly bloated if I eat too many. For some reason now eating too much candy makes me feel sick, (and also gave me very unpleasant heart palpatations from all of the sugar,) and with pizza it's the same way... too much, and I start feeling bloated in an unpleasant way. Also, I can't drink as much. One drink is enough to get me buzzed and a bit dizzy.
I'm not sure if it's HRT making me more sensitive to things, a change in body composition making me less resilient, or just age, I don't know, but it's really taken me by surprise. (And helped my weight loss, so I'm not complaining.)