I've been on Pred for a total of around three months. Started out at 40 mg and tapered 5 mg every week. I stayed the longest on 40 mg and while tapering on 15 mg because of worsening. All in all, Pred didn't help me at all with UC and that is why I say: Never again! I tapered it off, although I had almost most symptoms as when I started Pred. I didn't want to be on this drug in vain and we all know, Pred is a bit stronger than a handful of blue M&Ms ... .
Unpleasant side-effects I had include insomnia, anxiety, panic attacks, feeling shaky and weak, crying spells for minor reasons (or no reason at all), anger/fury/bad temper, feeling loopy and unreal most of the time. The only good thing was that I had beautiful facial skin - baby soft and not a single blemish on it. I was coughing a lot too and I think that was caused by the taste of the Pred pill. Sometimes it swam around in my mouth and I couldn't swallow it fast enough, so that yucky taste of that pill made me cough all day. I don't think that's a side-effect though. It was just me being inept to down it fast enough. My bad.
I didn't have the munchies at all and didn't gain weight. I lost my apetite on Pred, so there is hope for you - if you are worried about the munchies, that is .