I hate to confess this, but I'd like to lose weight. And I'd like to so it by cutting down calories and BIKING.

So here's my question. I have a mountain bike, but I have no pretentions.

Should I ride the bike on the roads, many miles, many hours? This gets my heart rate up to a steady pump and it stays there for 2 to 2 1/2 hours.

Or should I ride the trails for the same 2 to 2 1/2 hours and get that heart rate up to really REALLLY pounding, then relax, repeat. That's the way the trails around here in New England work -- rocks and roots for a short but strenuous uphill, then relax, then repeat.

Anyone got any advice? I can do both. Both are fun. I'm tired of NOT LOSING THE 10 LBS I want to lose. I want to be efficient. In the past I've used running, and boy does that work. But.....

Now I've got a bike. And I don't want to run any more.