Correct

吃素

/ chīsù / 
Strokes

Definition

to be a vegetarian

Example

As a Verb

abstain from eating meat; practise abstinence from meat; be a vegetarian/vegan/veggie; avoid eating meat and fish; live/feed on a vegetarian diet

1
Wǒ
我
gǎi
改
chīsù
吃素
le
了
  
。

I've gone over to (eating) vegetarian food.

2
Chīsù
吃素
rì
日

meatless day

As a Verb

[usu used in the negative]

3
Wǒ
我
yě
也
bú
不
shi
是
chīsù
吃素
  
。

I am not a person to be taken advantage of easily.

4
Wǒ
我
de
的
shǒuqiāng
手枪
bú
不
shi
是
chīsù
吃素
de
的
  
。

My handgun shoots to kill. / My handgun isn't for show only.