I just wrote up some of the numbers I have been trying to gather on the issue:
http://woodtrekker.blogspot.com/2013/09/living-off-land-delusions-and.html
The post is not intended to discourage anyone from trying it, or even to say it is impossible. I just wrote it in an attempt to get a better understanding of exactly what it would take to sustainably live in the wilderness long term.
Just a brief summary of the numbers I posted regarding how much of a certain plant or animal is needed per day per person in order to provide 3,300 calories:
Plants:
Cattail root - 26.5 pounds needed per day per person
Parsnips - 9 pounds needed per person per day
Blueberries - 13 pounds needed per person per day
Lingonberries - 41 pounds needed per person per day
Acorns (processed) - 2 pounds needed per person per day
Burdock root (unprocessed) - 10 pounds needed per [person per day
Animals:
Squirrel - 25 squirrels needed per person per day (as low as 16 if all of the internal organs are consumed)
Rabbit - 4 rabbits need per person per day (3 if all the internal organs are eaten)
Salmon (assuming 7 lb sockeye salmon) - one salmon will provide about two days of food at 3,300 calories per day
Turkey - one turkey will provide approximately two days worth of food at 3,300 calories per day
Deer (mature whitetail buck) - one deer will provide approximately 18 days of food at 3,300 calories per day (up to 21 days if the organs are eaten)
Black bear - one large black bear will provide approximately 21 days of food at 3,300 calories per day
*post edited to reflect that 10 lb of burdock root are needed per day rather than 100 lb. I was a decimal place off in my math. I apologize for any confusion.