Talked about, as one embarked on a high-cholesterol diet (6,3,3)

'talked' is the definition.
I don't know anything about this answer so I can't judge whether this works.

'about as one embarked on a high-cholesterol diet' is the wordplay.
I cannot quite see how this works, but
'about' could be 'c' (abbreviation for circa) and 'c' is located in the answer.
'one' could be 'the' (both can introduce a definite example of something) and 'the' is located in the answer.
'on' could be 'at' (I've seen this in other clues) and 'at' is found within the answer.
'high' could be 'h' (abbreviation) and 'h' is present in the answer.
This explanation may well be incorrect...

Can you help me to learn more?