Ram said, " I have taken food".
Just because Ram uses a perfect tense in his sentence doesn't mean you have to use one to report it. The reported version is "Ram said that he had taken food."
Also, the reporting verb is sometimes in the perfect form if that is appropriate.
"Because Ram had said he had taken food, I began to wonder if he was a thief." (Note that "taking food" rarely means "eating". I'm assuming here that he stole it.)
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