Food taken aboard in large quantities (6)
I believe the answer is:
stacks
'quantities' is the definition.
(stack is a kind of quantity)
'food taken aboard in large' is the wordplay.
'food' becomes 'tack' (informal term for food).
'taken aboard' indicates putting letters inside.
'in large' becomes 'ss' (I can't explain this - if you can you should give a lot more credence to this answer).
'tack' going within 'ss' is 'STACKS'.
Can you help me to learn more?
(Other definitions for stacks that I've seen before include "Orderly heaps as of hay" , "Tons" , "Ricks" , "A lot (of hay?)" , "Large tall chimneys" .)