Grub from us in mobile canteens (10)
I believe the answer is:
sustenance
'grub' is the definition.
(thesaurus)
'us in mobile canteens' is the wordplay.
'in' indicates putting letters inside.
'mobile' indicates anagramming the letters.
'canteens' with letters rearranged gives 'stenance'.
'us' placed inside 'stenance' is 'SUSTENANCE'.
'from' acts as a link.
(Other definitions for sustenance that I've seen before include "Food and drink" , "Nutriment" , "cooking provides this?" , "Nourishment" .)