The most common and most likely answer to this crossword clue is the 9 letter word INGESTING
I've seen this crossword clue in Financial Times
I
N
G
E
S
T
I
N
G
Buddy explains!

The straight part
We know that "Eating" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case eating = ingesting.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.
What does INGESTING mean?
INGESTING verb- To take a substance (e.g. food) into the body of an organism, especially through the mouth and into the gastrointestinal tract.
- To bring or import into a system.