Albert Barnes Commentary Exodus 16:35

"And the children of Israel did eat the manna forty years, until they came to a land inhabited; they did eat the manna, until they came unto the borders of the land of Canaan." — Exodus 16:35 (ASV)

Did eat manna forty years - This does not necessarily imply that the Israelites were fed exclusively on manna, or that the supply was continuous during forty years. Rather, it means that whenever manna might be needed, owing to the total or partial failure of other food, it was given until they entered the promised land.

They had numerous flocks and herds, which were not slaughtered , and these provided them with milk, cheese, and, of course, a limited supply of flesh. Nor is there any reason to suppose that during a considerable part of that time they may not have cultivated some spots of fertile ground in the wilderness.

We may assume, as in most cases of miracle, that the supernatural supply was commensurate with their actual necessity.

The manna, in fact, was not withheld until the Israelites had passed the Jordan.