I'm on herbalife and I take fiber powder well I actually add it to my smoothie, I was told that it doesn't necessarily help you lose weight but it does help get everything moving in the right direction if you know what I mean It also keeps me feeling fuller a longer period of time IMO. Hope this helps.
I can't say "YES IT WILL!" but I noticed that it did help me a bit, last year I got into one of my "I have to lose weight" kicks and bought some Benefiber powder since I heard fiber helps the stomach feel fuller for longer. It could have just been my mind but I noticed that it somewhat did do that and I was beginning to drop the pounds....unfortunately I got over that health kick and went back to my poor habits and stopped taking it but I would recommend it for sure, the worst that it can do is help your bowel movements but hey thats not so bad