This is an excerpt from Advanced Sports Nutrition-3rd Edition by Dan Benardot.
The pregame meal often comes 4 to 5 hours before the game, guaranteeing that you will arrive at the game with low blood volume, low blood sugar, and depleted liver glycogen unless you consume the right foods and beverages at the right times. Blood sugar is the primary fuel for the brain--if it drops, you can develop mental fatigue, which will lead to muscular fatigue even if your muscles are full of energy. However, if you start the game with food in your stomach, you will feel both bloated and nauseous, which will compromise your performance. Your goal is to consume enough energy and fluids at the times between the pregame meal and game time to assure that you step on the field optimally hydrated and with normal blood sugar, but with nothing left in the stomach that could make you feel queasy.
The strategies in the table on 441 will help assure that both your hydration and blood sugar are optimally satisfied, and that nothing will get in the way of you performing at your best.
From D. Benardot, Advanced Sports Nutrition, 3rd ed. (Champaign, IL: Human Kinetics, 2021).