well, there's the whole "growing in to the show" theory... But even then I'd think you'd need a couple of days to take the water bloat off. It's very individual. But even guys that were in shape all year round, like shawn ray, had offsean bloat.
And then there's the trenbolona trenbologna cattle fuel that doesn't give bloat but on the olympia level you can't just do that solely.