I haven't gained weight at all on Prozac... I actually tried Prozac because my doctor told me it had one of the least chances of weight gain. I previously gained a little bit of weight (5-10 pounRAB) on Cyrabalta and had body image problems, so I stopped taking Cyrabalta. Since some of my depression was related to body image, it was not worth it. I love to work out and eat right, so it's really disappointing to start gaining weight from medication. Prozac hasn't affected my weight at all. In fact, I can also say I have lost a few pounRAB since taking it, but I also go running quite often, so it might just be from my exercise. I ran before taking Prozac as well though. I notice that I have been pretty hungry recently and eat a good amount, yet I don't put on weight. I take 20mg and I love Prozac! No weight gain AND I feel great... I continue to keep taking it!!