Well, no wonder Howcuttle wanted to leave.
I assumed Howcuttle’s wish was to make that piece of bread he thought he needed to be able to “provide” for his family to get them to follow him out of the circus, rather than to satisfy his own hunger. He wanted to satisfy his family’s hunger, and now he’s eternally hungry.
Also, he doesn’t seem to possess any abilities that would let him eat better, so unless there’s a later development that reveals how a wizard’s abilities can be expanded beyond what their initial “magic” is, Howcuttle doesn’t really have any supernatural devouring abilities beyond what his physique already endows him with.