Um, well, I was on a bunch of doses of effexor, but started at 75mg (ended at 450mg) and I gained weight dramatically the entire time even though NOTHING about my eating habits had changed. Its 3 years after I QUIT taking it and I still have serious issues trying to lose weight. Exercise and healthy eating do nothing to help me lose this weight. My pdoc said that some people just continuously gain weight when on psychotropic meds. I hate it. HATE HATE HATE IT! Its to the point that I eat less than my 8 year old and lose zero weight.
As far as I've read about effexor (and I've read a lot because of all the problems I had on it) it always is a weight gain drug. I've never read where anyone lost weight on it. That's just my experience. But I wanted to share it at least.
I hope you find a solution. If you do, please share.