My thoughts(and let me say I am by no means a expert on this just follow this for my own purposes)are that you probably want to make sure the glycogen is topped off the night before and then not eat anything right before ,during or immediately after(water of course).For a short ride You may want to try to pick up the pace as much as possible and even try some intervals where you alternate periods of sprinting with slow paced recovery.This burns a larger percentage of carbs but much more calorie altogether so you may actually burn as much if not more fuel from fat this way and plus with the high intensity your metabolism remains elavated after training continuing to burn fat particularly if you avoid the post ride simple carb fest.My thoughts on your question to vlad on the snacking thread are that during and immediately after exercise (particularly intense )it is OK to injest simple carbs as snacks as long as it is immediately being used for fuel and not overwhelming bloodsugar levels which causes the spikes in energy.In my opinion while touring you still want to injest more balanced small meals at longer rest stops at regular intervals and I have no problem myself on bike while touring combining small amounts of fat (such as nuts)with simple carbs such as fruit as long as my pace at the time is slow and I don't speed up too much right after but I have a naturally high metabolism so my experience may or may not be useful to you.