She was very hungry because she didn't eat all day.

[keannu]

source : Grammar Zone Basics, 32p, C3

Q. Please fill in the blank.
She was very hungry because she ______________________ all day.

The answer is "hadn't eaten" or "didn't eat" when there is little term between the two actions.
Is the latter case of "didn't eat" correct?

 

[keannu]

There is little time gap between the two actions. The grammar book explains like that.

She was very hungry because she didn't eat for a short time.

 

[Tarheel]

Perhaps:

She was very hungry because she hadn't eaten all day.