Those garmin/polar/etc... calorie numbers are why many cyclists/runners etc. wonder why they're not losing the weight they want or expect. The estimates seem to be grossly overstated, so rather than try to make sense of them by arbitrarily calculating percentages or something, I just don't pay attention at all to them. There are plenty of other things worth your time and attention when it comes to riding, things more accurate than a shot in the dark guess at how many calories you've burned.

-Jeremy