it's like a bank account. the more you take out the smaller you get. Last year I took up cycling again after about 20 years off. It took me about 300 miles before I started to notice a difference in the way my clothes fit and how I felt. I lost about 50 pounds last summer and only rode about 1200 miles without depriving myself of the foods I enjoy. Problem is I gained back 40 over the winter even with riding the trainer a few times a week. I hope to do 3600 miles this year and a century per month from May to October with a handful of XC MTB races thrown in as well. I should talk...but it needs to be a lifestyle change. My best friend was well over 400# a number of times in his life. Up and down, yo-yo diets and exercise. Last year he switched to being a vegetarian and got serious about exercise. Let's just say he is less than 1/2 the man he used to be. He is 6' 2" and now right around 200#.