Your intuition to eat when hungry is incorrect with reference to getting you leaner. "Hunger" is caused by the secretion of a hormone, ghrelin, which happens to occur when growth hormone is released. In fact, not only does the drop in blood sugar and therefore decrease in insulin help engender growth hormone production. Ghrelin itself stimulates growth hormone release (http://www.nature.com/nature/journal/v402/n6762/full/402656a0.html). Growth hormone protects muscle and promotes fat loss. If you think hunger is a helpful predictor of when you should eat, you are exactly mistaken. Being hungry is the primary symptom of profound body fat loss. Ask anyone who has ever gotten extremely lean, and they will tell you that they gleefully embraced the painfully deep hunger that accompanied their morning fasted cardio sessions precisely because that is the only time you know for certain that you are losing body fat. The more hours and more frequently you do this, the leaner you will get. As long as you continue to stress skeletal muscle regularly and average a daily sufficient nutritional intake, you will lose zero lean mass in the process.