The first time he accidentally swallowed a spoon, it took him ten minutes to figure it out.
The second time took five...and this time he threatened himself: if he swallowed an eating utensil again, it might be a fork.
Wally stopped eating too fast after that.
Until today, that is. But after helping out around Central City and then transporting his oh-so-hungry molecules up to the Watchtower, Wally realizes that he really is hungry and that he's old enough now to watch his utensils as he eats and make sure they don't go anywhere bad.
So it's definitely disconcerting when (after hearing that he totally blew the turn-everyone-into-apes and vanishing thing) Grodd's voice pops into his brain–hello, Flash–and suddenly his fork vanishes from his hand.
Wally freezes instantly and realizes that he's still not old enough to watch his utensils when he eats.