Or HaChaim on Genesis 47:13/אור החיים על בראשית מ״ז:י״ג

1 ולחם אין…כי כבד הרעב מאד, there was no bread…because the famine was very severe, etc. The Torah informs us of the psychology of hunger. During a famine people have a tendency to eat inordinate amounts of food thus causing their reserves of food to be depleted prematurely. The author describes a personal experience of famine in the country he lived in where a person ate ten times the amount of food he would eat normally and still felt hungry.