You don't eat enough fruit

[ROBINDESBOIS]

you don't eat enough fruit vs you don't eat too much fruit.
Is you don't eat too much fruit very incorrect??? It sounds Ok to me because I am a Spanish speaker and if I translate it directly from "no comes demasiada fruta", it sounds ok.

[Rusty]

"You don't eat too much fruit, do you?" would be one way to say that you noticed someone's lack of fruit in their meal/diet. You're giving an opinion, but in a non-threatening way.

"You don't eat enough fruit" sounds as if you're diagnosing an issue someone is having, giving a little doctorly advice. You'll come across as asserting that the other person needs to change their diet.

[wrholt]

Depending on differences in context or in intonation and emphasis, your sentence "you don't eat too much fruit" can mean either "no comes demasiada fruta" or "no comes mucha fruta".