I lost plenty of weight by diet, and no exercise years ago. I can still do that now, but it is harder. I do both diet, and exercise. Exercise isn't enough for me. It usually increases my appetite. I have lost 50 lbs, and I have kept it off for 2 years. I exercise/workout everyday. The bike is just part of it. I have also learned after you loose a lot of fat, and working out, you start gaining muscle weight. Im 6'2" and 195. 185 was my low, but my waist is smaller, and my arms, chest, legs are bigger now. Muscle weight. Weight is just a number, as long as you look good, feel good, and at a healthy range of weight. Jmo I eat clean, and do low carb. I have one cheat day a week, usually Saturday.