My sister works at GNC and she brought home some of those lean shakes and man let me tell you those things taste soooo good. The vanilla is my fav and i'm looking forward to try the cookies n creme and the banana mmmmm sounds so yummy ^_^. Anyways my question is that do you have to exercise when you drink this. I've been taking them for a week now but I really don't need to loose weight I just like the way it taste but I think I gain one pound from it : (. My sister is trying to loose weight and she been on it as long as I have and she lost 5 pounds already.