The average American carries enough excess poundage so that might not be an unreasonable estimate. however, the key issue is "In what environment or circumstances. most of us can do pretty well in an area we know and understand, but it is a whole different ball game in an area with unfamiliar resources. I would do pretty well in the semi arid American Southwest, but i would be clueless in a tropical rain forest, although I would try not to feed the piranhas.

If I ever have to make it for two weeks, I hope it is a seashore environment with abundant tide pools, like the California Channel Islands. Lots of terrestrial goodies, as well....