Fiber with a little bit of fat is your friend! Try some whole grains, old-fashioned or pinhead oatmeal with fruit, or some lentils, beans, or fresh or steamed veggies, all with some moderate healthy fat like peanut butter, yogurt, or olive-oil vinaigrette. The fiber will fill you up and the fat will keep you feel satisfied.
I just started HRT too, and I've noticed my appetite increased significantly. I'm snacking on fruit and veggies, sometimes nuts in moderation. I find it takes at least half an hour after I've stopped eating for my stomach to feel really full and stop yammering, so I try to carefully control my portions at mealtimes.
