Elmer, the Unruly

When Elmer, the Unruly enters the battlefield
exile all food tokens.
Elmer, the Unruly's power and toughness is
equal to the amount of food tokens exiled
this way.
When a food token enters the battlefield, exile it,
Put a +1/+1 counter on Elmer, the Unruly and
it gains indestructible until end of turn.