该吃吃，该喝喝。(Gāi chī chī, gāi hē hē. )To eat and to drink as your will——to enjoy your life; take it easy.

Explanation

“该吃吃，该喝喝”这个短句的意思是，你享受你平常享受的事情，不要被一时的烦恼所困扰，主要用于劝说和安慰别人，让别人放宽心，不要过分忧虑。
“该吃吃，该喝喝(Gāi chī chī, gāi hē hē.)” is usually used to advise someone to enjoy himself and not to worry too much.
Words:

享受xiǎnɡshòu:enjoy;
快活kuàihuo:happy.

Sentences

1、 Jiă: Wǒ hěn dānxīn xià ge xīngqī de kăoshì ,chībúxià yě shuìbùzháo.
甲：我很担心下个星期的考试，吃不下也睡不着。
A: I am seriously worried about the exam next week and I can not eat or sleep well.

Yǐ: Gāi chī chī, gāi hē hē， bú jiù yíge kăoshì ma?
乙：该吃吃，该喝喝，不就一个考试吗？
B: Take it easy, isn’t it just an exam?

2、Jiǎ:Nǐ zěnme huóde nàme kuàihuo?
甲：你怎么活得那么快活？
A: Why are you always so happy?

Yǐ: Shì’a, wǒ yùdaò shénme shì cónglái bù wăng xīnlǐ gē, gāi chī chī, gāi hē hē.
乙：是啊，我遇到什么事从来不往心里搁，该吃吃，该喝喝。
B: Oh, beause I never keep anything bad in mind, just to enjoy myself.