"They eat too much sugar."
Translation:Jedí příliš cukru.
Only hypothetically, it is really strange. It could be an answer to someone implying they didn't but in reality I one would almost certainly phrase it differently. E.g., with the pronoun: "Oni příliš cukru jedí." - that sounds better, but still would make better sense if it were about eating enough sugar and not too much sugar. Most likely is just: "Oni jedí příliš cukru.".