Ahhhhhhhhh....I know exactly how you feel. I've always been a chubby guy and had to work very hard when I was younger to get in great race shape with a low body fat %. A HR monitor will be a good tool for you as you will be able to stay in that fat burning mode for as long as you like. And you'll be able to "kick it" to improve your anaerobic performance as well. If you really want to get scientific here, look into macro and micro cycles in training and develop a very specific training schedule. Make sure to have fun with it though, you can burn yourself out fast if you don't. Also, keep a training diary to include your waking heart rate. I found a great deal on a polar monitor on Amazon.com of all places and can view all my HR info on my laptop. So, if I wanted to I could see the same ride on different days to see where I was that day as far as recovery and fitness.