Calorie-Count About.com Health
Calories Burned for Activity: Bicycling
BMX or Mountain

578 calories per hour

Assuming a body weight of: 150 lbs
This is equivalent to eating any of the lines of the following table.

Quantity Description Cals
2.2 Grande Starbucks Caffe Latte - Made with whole milk 260
0.8 McDonald's Big Mac - With cheese 704
7.3 Glasses of wine (3.5 fl oz) 79
2.1 Snickers Bar 273
2.8 Cans of Coca-Cola 207
19.3 Carrots 30