fatten (one) up with (something)(redirected from fatten them up with)
fatten (one) up with (something)
To cause one to gain weight or become fatter by feeding them something in particular. The noun or pronoun can also come after "up." A: "Wow, your mom made quite a feast!" B: "I know, she seems determined to fatten us up with all our favorite foods." We need to fatten up these scrawny little kittens with some solid food.