The brain needs sustenance in the form of glycosides and carbohydrates in the morning to jump-start your whole system. When you don't have enough, you will start developing symptoms such as fatigue, loss of concentration, physical and mental exhaustion, and even insomnia. All these symptoms could occur within a matter of hours to as long as a period of several days. Your body is like a machine, so fuel it up. My best advice would be to at least put something, anything , in your mouth before you step out the door.
Moderation is key.
If you already drink lots of orange juice, great. To make it even better, try the kind with more pulp in it. The pulp will fill you up faster, and help regulate your digestive tracts. Many of the nutritional ingredients found in oranges are actually found within the pulp. Another great way of having juice is putting it in your cereal.