An adjective used to describe someone who can eat an abnormally large amount of food without getting full.
Originally derived from 'Whopper', the burger from Burger King. One who could eat three in one sitting was considered 'unwhoppable'. The term later expanded to include all large meals.
Also see Whopped.
"Ben is unwhoppable. He ate the Golden Corral out of business."
"I thought the doughnut eating contest would be a push-over, but for a skinny little girl, she is suprisingly unwhoppable."