Summon forth the original fat chocobo. Of course, being the original, it can eat much more than its peers.
Maybe not larger, but definitely more in charge, this most gluttonous of gluttons inspired the others to great weights. Although most modern chocobos have yellow plumage, historic tomes portray birds covered in feathers whiter than the whitest snowfall─ All the better to see the stains of its many meals.
Heave...heave...huff...huff... - Original Fat Chocobo