Metabolism Mess

Pinkie's metabolism has always been a thing of legend, consuming party cakes and legions of cupcakes only for it all to somehow melt away without so much as a pound landing on her frame. So legendary in fact that's it's captured Twilight's interest. Hoping to see if she could possibly help the medical world by learning how Pinkie's insane metabolism works and with Pinkie's approval begins experimenting on her. When one experiment is actually successful where Twilight is trying to see if she could transfer Pinkie's metabolism to another pony, things get out of hoof. Pinkie doesn't seem to care rather or not her body can manage her high intake of sweets, they're still going down the hatch, and soon enough the baker's going to look like a rising piece of dough herself. With the spell to transfer her metabolism back not working just how long can Pinkie's body go before even her monster metabolism won't be able to help her anymore?