Originally Posted by scrap
Pretty much like a Car. Check the Oil and Water, and make sure you top the Fuel up, before the journey.
Hot topic at the minute. The science is leaning towards the benefits of training fasted - at least for some of your sessions anyway.
The stuff about eating whenever you're hungry and 'stoking the metabolic fire' (whatever that means) is seductive. But the evidence at the minute seems to be that training whilst fasted promotes certain beneficial adaptations, most notably in the concentration of glycogen stored in the muscles.
The headline theory is that training when not completely nourished is an additional stress that has to be adapted to, essentially analagous to training with a reduced oxygen supply when altitude training.
There's also a cultural issue - breakfast (at least in the way we know it) is a relatively recent invention.