Each to their own. I exercised before this diet but have only tried once or twice while on the diet and it has put me off wanting to try again. Our bodies are under enough stress at the moment just being on this diet, by over doing it with the exercise you may notice a slow down with the weight loss because you could start gaining muscle and that could dishearten you? For me I got so light headed and felt like I wanted to vomit so I haven't tried since. My advice to you would be to just listen to what your body is telling you, if you need a rest then take a rest. If you feel ok then go ahead with it but don't do any vigourous exercise. I have started walking to work and back and find this is all the exercise I need! X x x