Weight watcher might stew about a pound (7)
I believe the answer is:
slimmer
'weight watcher might stew about a pound' is the definition.
I can't tell whether this defines the answer.
'stew about a pound' is the wordplay.
I cannot really understand how this works, but
'pound' could be 'l' (the pound sign is based on an L) and 'l' is located in the answer.
'stew' could be 'simmer' (I've seen this in another clue) and 'simmer' is found in the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for slimmer that I've seen before include "More slenderly built" , "More slender" , "thinner" , "with less fat" , "One attempting to lose weight" .)