Crossword Genius

If fat, side salad could make you healthy (2,3,2,1,6)

Ross

I believe the answer is:

as fit as a fiddle

I'm a little stuck... Click here to teach me more about this clue!

'you healthy' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.

'if fat side salad could make' is the wordplay.
'could make' is an anagram indicator.
'if'+'fat'+'side'+'salad'='iffatsidesalad'
'iffatsidesalad' with letters rearranged gives 'AS FIT AS A FIDDLE'.

Can you help me to learn more?

(Another definition for as fit as a fiddle that I've seen is " in form!".)

I've seen this clue in The Everyman puzzle in The Observer.
Want a hint initially instead of a full solution? Install my app