Last of the low-fat cream (5)
I believe the answer is:
elite
'cream' is the definition.
(as in the cream of the crop)
'last of the low-fat' is the wordplay.
'last of' indicates one should take the final letters.
'low-fat' becomes 'lite' (light in calories).
The last letter of 'the' is 'e'.
'e'+'lite'='ELITE'
(Other definitions for elite that I've seen before include "Chosen ones" , "12 letters = 1 inch (type)" , "A privileged class of people" , "Aristocratic" , "A privileged group in society" .)