Sorry I did forget one thing. PEople trying to loose weight and mountain bike tend to 'forget' to eat. Don't mountain biking can burn upwards of 700 calories an hour on a big man. Sometimes ever more. Bike 7 hours a week and you burn 4900 calories (over a pount) a week. Remove just a few calories from your diet and you create a 2 pound deficet (sp) on your diet. This is MORE than enough for healthy weight loss. Anymore and say bye bye to the muscle. Proper nutrition will help a lot with not overtraining and making you love the sport for a long time.

Sorry for spouting I just felt like typing I guess