Something to eat but not bolt (3)

I believe the answer is:

nut

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'something to eat' is the definition.
(I have seen 'Vegetarian food' mean 'nut' so perhaps 'food' could also mean 'nut')

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for nut that I've seen before include "Lover < or partner to bolt f" , "needing to get tight?" , "Large, hard-shelled seed" , "Fanatic (slang)" , "Brazil, for instance" .)

I've seen this clue in the Evening Standard.

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