The old commentators generally understood this to mean that Elijah had no other food at all, and compared this long fast with that of Moses and that of our Lord (marginal references). But the words do not exclude the notion of the prophet’s having obtained such nourishment from roots and fruits as the desert offers to a wanderer, though these alone would not have sustained him.
Related Commentaries of 1 Kings 19:8
1 Kings 19:8
8 And he arose, and did eat and drink, and went in the strength of that meat forty days and forty nights unto Horeb the mount of God.