Meaning of “eat (sth) up” - Learner’s Dictionary

eat (sth) up

phrasal verb with eat uk us /iːt/ verb (past tense ate, past participle eaten)

B2 to eat all the food you have been given:

Be a good boy and eat up your spinach.

(Definition of “eat (sth) up” from the Cambridge Learner’s Dictionary © Cambridge University Press)