I always cheat when it is a 'nil' by mouth time for our cats ... we board them at the vet the night before ... and let them deal with it. I just could not refuse to feed a pleading cat. (of course we have 2 and you can't feed one and not the other).
She's not to eat from 9pm the night before, and I can drop her off at 8.30am, when they open, so really it'll just be the morning she should be fussing - but I just know that she'll be having one of her can't-be-bothered-eating days the day before and so will be looking for food all night. She gets so very very naughty when she wants food!