Originally Posted by terrymorse

3400 calories in 4 hours = 850 kcal/hour

Seems a bit high. Actually quite high for a 4-hour ride.

850 kcal/hr corresponds roughly to 236 watts, which is very high. No way could I maintain 236 watts for 4 hours. Pros can on a tough stage, but not we mere mortals.

A more realistic figure for a 4-hour ride would be 150 watts, or 540 kcal/hr.