Bears eat anything you or I will eat and a whole lot of things we won't. At least I'm not too keen about eating a winter kill deer that's laid out in the sun for many many days. For a bear, the extra bugs are just more protein.
Now with that wonderful image in you mind, let's move on. Just about everyone I know who lives out in the woods, and quite a few people who live in town are having bear troubles. The bear population is up and there's not much wild food this time of year. Because of that, they are hanging around houses, eating pet food, raiding bird feeders, and pawing through garbage. Some have even taken to breaking into people's houses.
There's a few lessons here. The first one is don't leave any food around where bears can get it. I haven't even put anything in my compost bin since they've been hanging around. Another lesson that most people won't think of: bears, animals that evolved to live in these woods, can't find enough to eat. How does that make all you live off the lands type feel about your chances of making a go of it?
A few hundred extra bears in these woods is a population explosion that the environment has a hard time supporting. How will it support thousands of back to the land type people? Not too well, I think. That's one of the reasons it's important to be able to produce and store your own food. Every little bit helps. Garden like you life depends on it, it just might.
I could live off the land if I had to right now. I've tried it and actually picked up a few pounds. How was I successful where the bears weren't? Man is a tool using animal. With my fishing gear, I'm more efficient than a bear at catching fish. With a gun, I'm a better hunter. With fire, I can cook and process things into a more edible form. Bears don't dig up cattails and boil them up for dinner.
Of course, in desperate times, you won't be competing so much with bears as you will with other humans. The tool using animal can harvest more food, it's true, but the environment has limits. During the Great Depression, wild game was in short supply around here. Hunting seasons and licenses didn't matter too much to an out of work father with 6 hungry kids at home.
Knowing how to survive in the wild is a useful skill set. Learn to expand the number of wild foods you can eat. Go beyond fish, deer and rabbits. Try some frogs, turtles, crayfish, or snakes. There are foods that can be eaten in an emergency, like boiled inner bark of pine tree. I suppose if I got hungry enough, I could even eat a bear. FYI. Bears that have been eating out of dumps taste like garbage.
If you ever have to live off the land, make sure you have the tools and skills needed. It's nice to add wild foods to your diet out of a sense of adventure or for variety. It's tough when you need them to survive. Ask any bear.