"Big event" is too generic. What would be good nutrition for a 200k bike ride might be really different from a 10k-20k XC race. Eating before an XC race will be more like before a MTB race. Your competitors will have you on your redline right out of the gate and it's going to be like that for the next hour. Steady very hard, plus big surges on the climbs. Barf-proof and super high energy is what you'd want.