From my experience it depends on the amount you take.  Serveral years ago I took 400 a day and lost 35 pounds (weight I had gained from other meds I had since stopped)...BUT the problem was I couldn't eat -nothing looked good although I was very hungry.  I also had severly abnormal thinking.  I did not realize it was the meds at first-I thought my symptoms were due to my Mom being diagnoised with severe dementia and I was unable to deal with it.  As soon as I decreased to 100 day my psych. symptoms stopped-it took a while to regain my desire to eat.  Of course, you or anyone else may not have any of these symtoms.  I will tell you as I lost weight the feeling of the not needing food became painful and I couldn't sleep because I was so hungry-obviously I was taking much more med than I needed but only you and your doctor can decide that.  Although I had initial problems, Topamax has been the best thing for my migraines.  Only you and your doctor know what is best for you.