Dope low in fat (6)
I believe the answer is:
skinny
'dope' is the definition.
(I've seen this in another clue)
'low in fat' is the wordplay.
I cannot really see how this works, but
'in' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for skinny that I've seen before include "Unattractively thin" , "Very slim" , "Euphemism for a caffe latte with skimmed (non-fat) milk" , "little of substance?" , "Emaciated" .)