Why do angels eat if they are immortal? Scripture is silent about whether manna is an instrumental means for strengthening them, or if it is simply given for their pleasure. Nor does the Bible satisfy our awkward curiosity about the angelic digestive process—are angel guts, if there be such a thing, so efficient that they have no need to expel waste as we do? Or are there bathrooms in heaven? Of this much I am confident, whatever their bodily functions may consist of, angels do not suffer from embarrassment as we do. I suggest that will be the case for us as well in the new creation.
Are we going to eat manna forever? Perhaps, but I surmise that we will eat other things as well. That our diet in the age to come will consist of more than manna seems evident in passages which say that we will feast and drink wine. King Solomon's reign was a typological picture of the glory awaiting us in the kingdom to come. I believe something is foreshadowed in these words from 1 Kgs 4:20, "Judah and Israel were as many as the sand by the sea. They ate and drank and were happy."
Whatever such passages signify, it is hard to imagine the new earth being less abundant than the garden in which God placed Adam, full of every variety of pleasant things to eat. I suspect we will have new foods to match our new bodies. Regardless of what we shall find on that glorious menu, we can be assured that we will not suffer from the same degree of fickleness that presently afflicts humankind. Like bees, the angels do not tire of their honey bread. Even so, God will enable us to find delicious enjoyment forever in the cornucopia of delights he is preparing for his children.