一口吃不成胖子

yī kǒu chī bù chéng pàng zi

lit. you cannot get fat with only one mouthful (proverb)

fig. any significant achievement requires time, effort and persistence

一

yī

one

口

kǒu

mouth

吃

chī

variant of 吃[chi1]

不

bù

no; not so

成

chéng

short name for Chengdu 成都[Cheng2 du1]

胖

pàng

fat

子

zi

noun suffix, as in 椅子[yi3 zi5] "chair"