Pinkie Pie never sleeps because of her sugar.
IT ALL MAKES SENSE NOW.
Pony flesh is probably full of sugar, or has sugar instead of blood.
Since of their non-aerodynamic and heavy bodies, and how they have a lot of confectionery in their diet, how would you think they could fly?
They obviously need lots of sugar for energy.
Pinkie Pie obviously thrives on the sugar of other ponies.