Cat takes to a new food (6)
I believe the answer is:
tomato
'food' is the definition.
(tomato is a kind of food)
'cat takes to a new' is the wordplay.
'cat' becomes 'tom' (a tom is a male cat).
'takes' is an insertion indicator (take can mean to capture or invade).
'new' indicates an anagram.
'to'+'a'='toa'
'toa' with letters rearranged gives 'ato'.
'tom' put inside 'ato' is 'TOMATO'.
(Other definitions for tomato that I've seen before include "It used to be call a love-apple" , "It's also known as a love apple" , "Fruit used in salads" , "Pulpy edible fruit" , "Love apple (or "beef" fruit?)" .)