Use the axiom: Train on Fat. Race on Carbs.
This will adapt your body to preserving carbs so you will be better able to sip from the glycogen gas tank and guzzle from the fat gas tank. Then on major events, by all means shovel the carbs in anyway you can get them. Note that on Mike Foote’s recent 24 hour record he was eating anything he could and drinking soda pop.
Scott