It wont really help with the weight loss no. Saying this, what it will help with is toning you up and making you fitter. Not all slim people are fit! I think exercise is good on CD to help tighten loose skin, tone your body and help the heart! I have always exercised whilst doing CD, and I'm much fitter, and don't have much loose skin. Admittedly I do use soap and glory firminator as well (it's fabulous!) but exercise is defo the way to go, and they do say that walking is the finest thing!
Hugs x x x