puppy fat 少儿肥胖；小儿虚胖(长大后消失)

【例句】
After Jane lost her puppy-fat she became very slim.
简发育期间出现的肥胖消除之后，显得十分苗条。

It wasn't easy to lose puppy fat when Mum fed her on stodgy home cooking.
母亲给她吃易饱的家常菜，她想减掉婴儿肥可是很难。