Crossword Genius

After starchy food, relatives put on stones (10)

Ross

I believe the answer is:

carbuncles

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'on stones' is the definition.
The answer and definition can be both substances as well as being plural nouns.
Perhaps they are linked in a way I don't understand?

'after starchy food relatives' is the wordplay.
'after' means one lot of letters go next to another.
'starchy food' becomes 'carb' (I've seen this in another clue).
'relatives' becomes 'uncles' (uncle is a kind of relative).
'carb'+'uncles' is 'CARBUNCLES'.

'put' is the link.

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I've seen this clue in The Sunday Times and The Times.
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