If it's only taking distance, speed and weight into account, you get rides like mine yesterday.

To the LBS: 16.27 miles into a 16-20 mph headwind with 30 mph gusts. It took me 1:10. Computer says 655 calories.

From the LBS, 16.22 by a slightly different route. Thankfully the wind hadn't changed and it blew me all the way home in 0:54. Computer says 795 calories.

I think I probably burned a lot more calories on the upwind leg... even if I was going faster the other way!