Drink to health food for breakfast (5)
I believe the answer is:
toast
I believe this is a quadruple definition!!
'drink to' is the first definition.
(synonyms)
'health' is the second definition.
(I've seen this before)
'food' is the third definition.
(toast is a kind of food)
'for breakfast' is the fourth definition.
(toast is often eaten as breakfast)
(Other definitions for toast that I've seen before include "Grilled bread - drink (to)" , "making this pledge?" , "Drink one's health" , "Drink the health of - brown bread!" , "Brown by radiant heat" .)