The most common and most likely answer to this crossword clue is the 9 letter word CALORIFIC
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More clues leading to the result CALORIFIC
- Accountant on mad frolic gobbles one, which is fattening
- Energy-producing US state alternatively provided Italy with carbon
- Opening cut on source of veal, not entirely fatty
- Label space deficient at both ends for heating
- Fattening fizzy cola borne by orifice, essentially
- Like unhealthy foods around large mouth, mostly?
Buddy explains!

The straight part
We know that "for heating" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case for heating = calorific.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 CALORIFIC mean?
CALORIFIC adjective- Relating to calories.
- Relating to or producing heat or other energy.
- (of food) High in calories and thus likely fattening.