The only place that people do what you are describing, living from unmanaged or lightly managed natural forest systems in the modern day is the tropics. Tribes still live in Africa, South America and Polynesia with little or no assistance from outside. It certainly can be done although these peoples are also quite experienced at it, there may be a bit of a learning curve to hunting and gathering all of your food successfully. Especially in more degraded ecosystems like you will find on most of the planet.
Like for example where I live, between the fact that most of the productive species are all dead or diminished and the general loss of forest productivity here I couldn't survive on less than at least a hundred or so acres. Even still my diet would be almost all
mushrooms, hickory nuts, a few kinds of wild greens, berries and whatever meat I could scrape together.
It would be much easier and just as friendly to the land to establish some managed (at least at first) food forest and gather from that and hunt the animals that gather food from it as well. It would certainly reduce acreage needs and be more realistic unless you want to live like a polynesian tribesman.
