Ehh just ride a lot. Having a powermeter will help in determining how many calories you burned, at that point adjust your diet accordingly.
Although at lower intensities you do burn higher percentage of fat, you also don't burn as many calories total. At higher intensities you burn more carbohydrates, but you also expand more energy so you burn more total calories. Plus part of the food you eat will be used to replenish your glycogen stores. Also side benefit of riding at higher intensity is that it boosts your metabolism slightly. So you end up burning 200-300 (don't remember exact number) calories. Problem with higher intensity is that you just can't keep it up for long, so you need to find a good balance: LSD! Which is Long steady distance.