Blub, blub blub...
The way this game works ensures that the winner is chosen as soon as the deck is stacked, you just don't know who it is yet!
In order to add a little more variety try spreading the food cards out face down and then allowing the the players to choose one from this pool rather than the top of a stack.
An addition to this would be to put discarded food back into the same pool.
An extra addition, again for older players would be to use the above variants but mix up the pool each time a tummy ache card goes back into the pool, or after any card if you like.
Will make the game a lot more interesting for the older players.