Vegetables have about 200 calories or less per pound. Seafood, poultry and meat anywhere between 400 to 800 calories per pound.
Just GOOGLE "Calorie Counts of Foods Per Pound" for greater detai.
A subsistence diet would probably require 3 to 4 pounds of food per person, a 2,000 calorie diet perhaps 4 to 6 pounds.
Assuming consumption of 4 pounds a day, a population of 300,000,000 will consume 600,000 tons of food per day.
That is a lot of porcupines, deer, dogs, fish, birds, bugs, worms, cattails, kudzu roots and palm hearts for people to forage every day. And the next day. And the next day.....
Especially when they live in cities.
"As of 2011, about 250 million Americans live in or around urban areas. That means more than three-quarters of the U.S. population shares just about three percent of the U.S. land area."
Ref: "American Cities On The Rebound"
http://www.cbsnews.com/news/american-cities-on-the-rebound/
Well done, the facts about food are totally unknown to most people.
Those who hunker down outside the cities will have it ok for about 3-5 weeks. After that, you'd best have lots of ammo and teams who can maintain and protect a perimeter. Ferociously.
Now you really have me missing Georgia! I could harvest Kudzu root for ever! Of course I have to spend every waking moment eating it and harvesting it, but I would never run out. In fact the danger is if you stand still to long while harvesting you will get smothered to death by the Kudzu as it grows.
In fact in my Prepper’s binder I have a great article on:
HOW TO GROW KUDZU
http://www.walterreeves.com/how-to-archive/how-to-grow-kudzu/
Enjoy!