Idiom: to eat, sleep and breathe
(something); used as a verb



First Example:
Janet: Have you seen Jamie lately?  She always seems to be busy.
Corey: Oh, she’s really into the World
Cup.
Janet: Really?  I didn’t know she liked soccer.         
Corey: She was never that interested
before, but ever since the World Cup started, she eats, sleeps and breathes soccer. 
If she’s not watching a game, she’s reading predictions or recaps.
Janet: Wow!
Corey:
I’ve never seen her this
enthusiastic about something. I wouldn’t be surprised if she dreams about
soccer.

Meaning: The idiom “to
eat, sleep and breathe (something)” is used when someone is  incredibly enthusiastic about something, focusing
all of their energy on that one thing. 
In the example above, Corey says that Jamie “eats, sleeps and breathes” soccer since the World Cup started.
 This means that Jamie spends all of her
time focusing on soccer.  Alternatively,
some Americans will use the slightly different idiom “to live and breathe
(something)” for the same meaning.

Valerie: How is your sister doing in school? 
Timothy: Great!  She finally decided on her major.
Valerie: What did she choose?               
Timothy: Guess.
Valerie: Well, ever since she was little,
she has lived and breathed ballet,
so I’m going to guess Dance?
Timothy:
And you are correct.  My parents were trying to convince her to
become a business major, saying it would be better for her career, but I’ve
never had any doubt she’d become a dancer.   

Meaning: In this example, Timothy’s sister “lives and breathes”
ballet, meaning that she dedicates all of her energy on ballet.  These two idioms basically mean the same
thing and different people will prefer one over the other (often based on age
or region).