The most common and most likely answer to this crossword clue is the 11 plus 3 letter word GINGERBREAD MAN
I've seen this crossword clue in The Times
G
I
N
G
E
R
B
R
E
A
D
M
A
N
Buddy explains!
The straight part
We know that "Kid's food" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case kid's food = gingerbread man.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.