As already mentioned, foraging goes against LNT and can also put a dent in wildlife food resources. An occasional "taste" doesn't do any harm, but if everybody did it...it becomes noticeable. Knowing what is edible is just as important a skill as general survival. Depending on those skills will gain you a big appreciation for what's involved and how easy it is to starve or freeze if you can't keep up. So, become educated. General foraging, primitive fire making, shelter building....what's the point when all that can be in a neat, lightweight package on your back? Use those skills as a backup.
Fishing and hunting is another matter where legal and regulated. I fish/hunt and consume my catch.