Interestingly, these gains were made without any conscious increase in calorie intake. I've continue to follow the same eating style described in my books. But I've gotten way ahead of myself. Briefly, here are the answers as I understand them. When the dietary supply is inadequate the body can make a limited amount of creatine from a combination of the amino acids arginine, glycine and methionine.
Creatine plays an important role in muscle contraction.
It helps replenish ATP, a chemical which is the immediate source of energy for all muscle contractions. ATP, therefore, must be constantly replenished. That's where creatine comes to the rescue. The resynthesized ATP can then be used again to fuel more muscle contractions. The more creatine in the muscle, the more times ATP can be quickly regenerated.