@James A Williams  
That’s a nice thought. XD
 
Also, as per the episode, forgot an hour, because she ate that massive cake in literally one second.
 
Literally, one second to scoff down an absolutely massive, four tier cake loaded with donuts, eclairs and a chocolate mouse head. A cake bigger than she was, that Big Mac struggled to carry, and was so big they had to remove the side of the train carriage to get it on board.
 
In one second, in one gulp, it was all gone, with the only evidence that the cake had ever existed being the plate, the stains on everypony, and Pinkie’s enormous fat belly.
 
There’s a reason why it’s my favourite scene. XD

Pinkie: Mm, mm, mmm! Super tasty.
 
Applejack: Sheesh Pinkie, that cake was huge and you ate the whole thing in less than an hour!
 
Pinkie: Aha, you know me, loving satisfying my tummy with all things sweet.
 
Applejack: Do ya ever feel full from eatin’ so much?
 
Pinkie: Nope. I could eat an entire county made of sweets and it wouldn’t feel like too much.
 
Applejack: Really? I’d sure love ta see that.