re: Medieval farmers ate 7000-9000 calories a dsy

In the book Undaunted Courage Stephen Ambose says the men of the Corp of Discovery ate 10k calories per day while rowing up the Missouri River. They had full time hunters just to harvest wild game.

Edit: I just looked it up he said 10 pounds of meat.
Venison is about 150 calories per 3 oz. About 800 calories per pound. So, that's about 8,000 calories per day.