With everyone concerned about eating extra calories over the holidays, I am here to tell you that you should eat ... before you exercise first thing in the morning. It seems that many folks think that if they work out on an empty stomach, their bodies will target fat. Unfortunately, that is just not true, and this persistent myth can actually set you back if you are trying to lose weight.
After fasting all night, since you don't eat while you sleep, your glycogen (or carb) stores are low. Glycogen is the fuel the body generally burns first for energy. If your glycogen levels are low and your body is in motion, your body decides to hold on to your fat. The body is essentially paranoid and thinks a famine might be coming, so it holds on to the fat as emergency reserve and targets muscle instead. This is not good, since you are working out to lose fat, not lean muscle. You want to keep lean muscle, because it will boost your metabolism.
The good news is that you just need to eat just a small amount to let the body know that fuel is on its way and you are not entering a famine. Just a simple snack that contains 100 to 200 calories will do. Me? I eat a banana and a small handful of nuts before a run, or I eat yogurt before a weight training session.