Is my sentence correct?(Japanese)?

Question:

Watashi wa karada ga oki ni naru hoshikunai desu kara,yoru sukoshi taberu you ni shite imasu.

Im hoping it means:

I'm trying to eat less at night because I don't want my body to get big(Fat).

Is there anything wrong with my sentence?

Answer:

"watashi wa futoritaku nai node yoru wa sukoshi dake daberu you ni shi-te imasu."
(you can replace 'node' with 'kara', if it's colloquial)

- In English 'big' can mean 'fat', but we don't use 'ookii' for 'being fat'.
- "oki ni naru hoshikunai" --> NG --> "don't want to" + "ookii" = "ookiku nari-taku nai"

"ookiku naru youni takusan tabenasai" is frequently used toward kids.