Why a lot of publications have came out over the last years saying that at lower intensities you burn more fatty acids and still while that is true, most of us don't have 4 to 5 hours a day to do that sort of training to get leaner. The fact is most of us want to get stronger too, while doing the work of our rides. The math break down looks like this but may not be what you are capable of. Lets say you burn 3 kals a minute at intensity that feels challenging yet your breathing is comfortable and is close to your 70% MHR~ that means in one hour you would burn 180 calories. 80% of those would come from fatty acids and 20% would come from glycogen. Therefor 144 kal would come from fat and 36 would come from glycogen now up the intensity to where you feel challenged and uncomfortable and are close to your 80% MHR effort for one hour burning 6 kals. You would burn an overall of 360 kals more calories but 50% would come from fat and 50% would come from glycogen or 180 each. The higher intensity burns more of both kinds of fuel and since you are pushing your self a training effect of overload comes into play. The thing is that after a very hard ride you need rest so that your body can compensate for the break down that you have given it. So how do I stay ahead of the game and burn calories and get good training effect in? Work as comfortable hard as you can with out hurting yourself physically defeating yourself mentally or need so much recovery you take away from your ride then and the one to come.
Velocity