More than one common healthy food (6)
I believe the answer is:
greens
This clue is a double definition.
'more than one common' is the first definition.
('green' can be a synonym of 'common')
'healthy food' is the second definition.
(informal term for vegetables)
(Other definitions for greens that I've seen before include "Leafy vegetables" , "Colours" , "food" , "Vegetables - on the golf course?" , "party politicians" .)