how long can the average human body go with out food?

Answer 1

There's a rule of threes:

3 weeks without food
3 minutes without oxygen
3 days without water
3 hours in a severe environment without protection

The lack of water out in the wild would kill you first. You could die in one day from dehydration if it's really hot, or if you are doing a lot of physical work, but 3 days without water is about the standard.

Answer 2

it really depends on the amount of body fat that the person has. with average levels of body fat a man or woman could survive for 3-4 weeks with out food. the more body fat that a person has the longer they would be able to survive due to the massive amount of energy that can be derived from stored fats.