There are a lot of vectors this discussion could take --- and HAS taken in past discussions of the same topic, though I don't recall for certain which forum(s). Here, whiteblaze.net, elsewhere, dunno, but you might search.

One vector is the morality and legality aspects; I'm not inclined to talk about that much as IMO the legality issue is pretty straightforward, call your local ranger district office and ask would be one approach.

Another is the utility. In previous discussions of this topic, it seems to me that the majority opinion has asserted that it's hardly worth it, as it's tough to get many actual calories that way. Thru-hiking the PCT this year I talked with a fellow early on who planned to heavily supplement his diet that way, so I ended up having this discussion with some other folks along the way. The time and energy (calories) needed to gather foods that provide much in the way of calories is generally going to be significant, especially if you plan to walk many miles each day. Obviously the specific opportunities vary by location, time of year, the legality/morality issue on a per-food-item basis, and your expertise and perhaps equipment (hunting, fishing).

Bottom line is that --- I believe --- few people that look into this sort of romantic notion end up getting a lot of food that way. Of course if your goal is to add a little spice to your food, picking some wild onions or the like is fun, nice. It's just not significant in terms of food value. If the whole purpose of your outdoor trip is to go out and live, but not move around a great deal in a natural setting, perhaps this can work out better. I don't know how much of the day our hunter-gatherer ancestors spent just keeping fed, but for an amateur like me, I wonder if there would be enough hours in the day (!), again, depending on when and where.

Again, search some sites for words like "foraging", "calories", etc and I would guess you can find existing threads that offer a variety of opinions (and who knows, maybe some actual experience ...).