A boxer normally has one even if not hungry (6,7)

'a boxer normally' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.

'one even if not hungry' is the wordplay.
I cannot really understand how this works, but
'one' could be 'i' (Roman numeral) and 'i' is found in the answer.
'not' could be 'con' (I've seen this in other clues) and 'con' is located in the answer.
This explanation may well be incorrect...

'has' is the link.

Can you help me to learn more?