The dietary needs of the elite and recreational sportsman and woman are complex and highly variable. The underlying need is to manage the blood glucose levels to avoid both peaks and troughs.
There are 2 scenarios that do not help althletes:
Peaks in blood glucose levels occur when we eat simple starchy carbohydrates, including sugar, and these highs then trigger a release of insulin which drives the blood gluose levels lower. Unfortunately the amount of insulin released can be soi large that the blood sugar levels then dip too low. The result is a serious drop in energy levels and that is the worst outcome for an athlete.
The other scenario occurs when you don't eat the right foods, after even moderate exercise, the blood glucose level drops below the normal level and yet again the body experiences an energy gap. This again doesn't help athletes.
In an ideal world blood sugar should simply fluctuate across a small band about the ideal mean blood glucose levels. This is not always easy to obtain but with Trehalose is is much easier. Eating the right carbs can dramatically improve sporting performance.