Depends a lot on the time of year. Actually, most fatalities from being lost in the wilderness occur through falls (e.g. trying to climb to higher terrain to get a direction) and drowning rather than from hunger or thirst. Hypothermia is another major problem. Death from attacks from wild animals such as wolves, bears, snakes, etc are also possible but do not occur that frequently in such situations.
Psychology, it is panic that can cause a big problem. As this man said, one big mistake is moving around if people know where you last were positioned. You cannot move that far by foot per day and that defines a search area quite tightly.
Actually a diet of berries and bugs is quite nutritious even if the bug bit is not so appetising. There are a number of companies being formed to develop insect food as a means of meeting future food demand from the global exploding population level: