Our body generates energy from 2 places:

1. Food – specifically the calories in food. That's all a calorie is, a unit of energy for our body.
2. Sleep – different type of energy from food, but equally as important.

If one of these areas is out of whack, chances are the other will be too.  We sometimes attempt to use food for energy when feeling tired when what we really need is a nap.  On the flip side, sometimes sleep becomes a way to avoid eating. It's hard to get 3 meals per day when you sleep 12+ hours. 

Artificial energy is not the same thing as real energy.  Things like caffeine, adrenaline, medications and other stimulants are no substitute for food and sleep.  They fake our body out and make it even harder to maintain the homeostasis the body desires.