Speaking about taiga implies average climate. If things happen neither in middle or eastern Russia nor northern or western USA or Canada, then these territories are quite dense populated and any healthy adult man should come to some road or settlement, or, at least, river within a week of walking straight.
Most healthy food will be various berries, but they exist only after the middle of summer. Depending on the area and time of year, you can find strawberry, raspberry, blueberry, blackberry, cranberry, lingonberry, stone bramble, shadberry, hawthorn (whitethorn), viburnum (at late autumn), elderberry (only black, ripe!). They are healthy and safe in any quantities. After some days of such diet your bowel will adopt and it will not cause any problems.
A good addition to berries can be oxalis leaves, Aegopodium (ground elder), nettle leaves, ramsons, fireweed, Stellaria (chickweed), silverweed, young Atriplex and Artemisia (mugwort) leaves, young coniferous shoots (as tea). These are common in most middle climate and in your area there may grow more edible plants. Dandelions and some other bitter weeds are also edible after soaking for an hour or two. I ate most of these plants. You can eat them in everyday life, especially in spring, as salads, soups or even pancakes with addition of some flour and egg. Fireweed leaves give nice healthy tea, untreated green or fermented black.
Birch and maple juice are at once drink and light food. Although they are most often harvested during spring, trees have juice during all warm season. To get juice we should make small V-shaped cut through tree bark, insert something like spout to guide juice into cap. Don't forget to cover the hole with resin after all!
There are mushrooms which we can eat without cooking, they are called noble. Although mushrooms are assumed as high-calorie food, they are digested badly, so they should not be eaten if there is vegetable food. Also, if you do not have an experience in mushrooms, you can make a deadly mistake. At last, they should be washed and you may not have enough water.
Hunt for small animals requires time and vigor, then they should be carved and cooked, and meat also is digested not as good as many people think. So, it could be advised only of you plan to walk more than 3 weeks and there are no other food.
Hunt for wolves, pigs, bears, moose is really dangerous even if you have a weapon. If you do not have an experience, injured animal almost certainly will kill or injury you. Almost all animals are faster and stronger than humans.