Let's say you are writing a past event of a diabetic patient to a doctor.
"The patient had consumed 1 whole canned juice of 'del monte' pineapple 240ml, which the patient usually consumes just a half of the juice. Also, 1 pc. of rice cake HAD EATEN/HAD BEEN EATEN as her late afternoon snack, before the blood sugar check.
As you can see, the patient had had her juice & a snack before the blood sugar test. But should I use had eaten or had been eaten?
Look at the word order:
The patient had consumed 1 whole canned juice
One pc of rice cake ....
In the first sentence the subject is the patient.
In the second the subject is the food, so the second sentence has been cast in the passive voice. The rice cake had been eaten.
The difference between the sentences in not in the tense, they both use the same tense: past perfect.
There is no real need to use the passive for the second sentence, so don't. I'm not sure what a cupsize of rice cake means. It's not clear what "it" refers to in "which is usually half of it".
The patient had consumed 240 ml of pineapple juice and one piece of rice cake before her blood sugar test. The pineapple juice is usually half of it.
