פירוש על בראשית 41:21

ולא נודע כי באו אל קרבנה, thus Pharaoh said to Joseph at this time; he only now remembered that at the time that he had been dreaming it had appeared to him as if there was no trace of these seven fat cows having come into the lean cows. However, at the time when he had dreamt, i.e. when the Torah told us what he had dreamt it would not have been appropriate to describe anything beyond the facts, i.e. that the lean cows had eaten the fat cows. At that point in the narrative there had been no call to describe Pharaoh’s subjective reaction to what he had seen.

ולא נודע כי באו אל קרבנה, analogous to the warning in Leviticus 26,26 that even when the Israelites would have food, eating it would not satiate them. We also have a statement by our sages describing the effect of food on those who have it (in the fridge) as being different than for those who run out immediately after having eaten their last provisions. The latter cannot feel the effect of what they have eaten because they do not know where their next meal will come from. (Yoma 74)

ולא נודע, concerning this comment of Pharaoh’s narrative Joseph said in verse 31 that ולא יודע השבע that during the years of famine the abundance of food during the preceding 7 years will not even be something people could remember.