from my rough calculations i seem to only burn about 15-20 calories per mile when bike commuting. so for my round trip commute mileage of 29 miles, that's 435-580 calories/day (depending on lake michigan heawinds).

and my ridiculously slow-ass metabolism only requires about 1,200 calories/day without any phyisical activity, so bike commuting allows me to bump that up to ~1,700 calories/day if i want to maintain my weight.

lots of people seem to think that bike commuting is this super-awesome way to get fit, but it you're cursed with a slow-ass tortoise metabolism like me, it's not really that big of a calorie burn.