fatten somebody/something ↔ up
From Longman Dictionary of Contemporary Englishfatten somebody/something ↔ up phrasal verbFATto make a person or animal fatter My parents are always trying to fatten me up. → fatten→ See Verb tableExamples from the Corpusfatten up• Will eating carbohydrates fatten you up or trigger diabetes?• We raise calves for sale to feedlots, which fatten them up to market weight.