My friend did this diet, and she lost a lot of weight by exercising. (Also eating small meals many times throughout the day to give her metabolism a workout) She worked out for almost 2 hours a day, 6 days a week, which I thought was a little too much and she got too thin very quickly, so I'm almost positive that the 30 minutes will suffice and be much healthier! I need to start working out too, but I'm on the South Beach Diet's rival... ATKINS! lol I'm thinking of starting the South Beach though, as Atkins is far too restrictive.