Genesis 9:3 - Clarke's commentary and critical notes on the Bible

Every moving thing that liveth shall be meat for you; even as the green herb have I given you all things. Every moving thing - shall be meat - There is no positive evidence that animal food was ever used before the flood. Noah had the first grant of this kind, and it has been continued to all his posterity ever since. It is not likely that this grant would have been now made if some extraordinary alteration had not taken place in the vegetable world, so as to render its productions less nutritive than they were before; and probably such a change in the constitution of man as to render a grosser and higher diet necessary. We may therefore safely infer that the earth was less productive after the flood than it was before, and that the human constitution was greatly impaired by the alterations which had taken place through the whole economy of nature. Morbid debility, induced by an often unfriendly state of the atmosphere, with sore and long-continued labor, would necessarily require a higher nutriment than vegetables could supply. That this was the case appears sufficiently clear from the grant of animal food, which, had it not been indispensably necessary, had not been made. That the constitution of man was then much altered appears in the greatly contracted lives of the postdiluvians; yet from the deluge to the day of Abraham the lives of several of the patriarchs amounted to some hundreds of years; but this was the effect of a peculiar providence, that the new world might be the more speedily repeopled.