This isn't rocket science... eat the same... make sure you have solid preworkout nutrition... if the event is long... drink some water or gatorade or bcaas/eaas..
Stick with normal foods no need to carb load unless your are doing an endurance type event. Keeping energy levels up on the day of the meet is most important for throwing events as usualy u have multiple throws spread out across the day. Use high energy snacks to prevent faiding later in the day.
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It aint just how much you lift but how you lift it
if your eating enough all the time you will be fine...if you want to just be sure, eat some extra carbs to make sure ur glycogen stores are full...maybe a couple plates of pasta or something of that nature
i wouldnt carb load if you were a thrower, maybe if you were running, but throwing a shotput or discus a few times isnt gonna require too much carbohydrate wise, just eat normally.