Tried to lose weight (6)
I believe the answer is:
dieted
'tried to lose weight' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for dieted that I've seen before include "Aimed to lose weight" , "Ate sparingly to lose weight" , "Tried to lose weight" , "Went on strict food regime" , "Regulated one's food consumption" .)