Though I would suggest (if you want to work on this project more), to inform the player of the fat amount when they reach it. For myself it only felt like a cool dynamic after you explained it.
Yeah, that's a good idea. We were thinking of putting the piggie sprite on the cornstore page so you can see it growing as you eat more donuts, and also include the "speed" which gets lower the fattier the piggie got, but then it was day 10 already :D