The most common and most likely answer to this crossword clue is the 4 letter word SLOP
S
L
O
P
Buddy explains!

The straight part
We know that "unappealing food" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case unappealing food = slop.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 SLOP mean?
SLOP noun- A loose outer garment; a jacket or overall.
- (chiefly in the plural) A rubber thong sandal.
- (in the plural) See slops.
- Liquid or semi-solid; goo, paste, mud.
- (sometimes in the plural) Scraps used as food for animals, especially pigs or hogs.
- (chiefly in the plural) Inferior, weak drink or liquid food.
- (sometimes in the plural) Domestic liquid waste; household wastewater.
- Water or other liquid carelessly spilled or thrown about, as upon a table or a floor; a puddle; a soiled spot.
- Human urine or excrement.
- To spill or dump liquid, especially over the rim of a container when it moves.
- To spill liquid upon; to soil with a spilled liquid.
- In the game of pool or snooker to pocket a ball by accident; in billiards, to make an ill-considered shot.
- To feed pigs
- (costers) A policeman.