In my cases (third time on HRT for me) it took about a month with just premarin and maybe after 2-3 weeks when I used spiro before I felt any changes. Androcur kicked ass within a week! As they say YMMV. About now is when to expect the roller-coaster ride to start! Keep plenty of tissues handy.
One thing on tastes in food I've been seeing from talking to other Ts in my group is a sudden craving for vinegar. I always had a propensity towards it and it sure is a lot stronger now. And of course, there is that wonderful synergy between estrogen and chocolate

Dark is better than milk, less sugar and more of the good stuff.
Hot flashes??? I wish! I am colder now then ever before. The A/C at work is always 70. Down in production areas sometimes lower! Give me the Florida Keys in August temperatures! I need to wear a full set of thermal undies in the summer, plus a sweater it is so cold inside. Being tied to a desk all day doesn't help to generate heat either. Funniest part of all this is my wife swears I am a nuclear reactor at night I throw out so much heat. But I was that way before HRT. Back then I joked about needing HRT for my night sweats, just like they said in the commercials on the tele