By increasing the speed to 12 to 14 mph, that person will burn 198 calories in 20 minutes. A 200-lb. person will burn 120 calories with a leisurely bike ride, but traveling between 12 and 14 mph will burn 264 calories in 20 minutes. A 240-lb. person will burn 144 calories in 20 minutes, while more vigorous biking will burn 317 calories.