There are three things that the fit and healthy human body needs to consume in adequate quantities, in order to survive indefinitely beyond something in the order of a month:
(a) oxygen,
(b) water;
(c) edible (non-poisonous) food;
I have heard it said that (barring certain exceptional circumstances)
as a rough rule of thumb, we can be expected survive:
(a) something in the order of 4 minutes without oxygen;
(b) something in the order of 4 days without water;
(c) something in the order of 4 weeks without food;
If your question implies "survive with neither food NOR oxygen", then the answer is:
under normal circumstances, about four minutes
(but at abnormally low temperatures, e.g. completely submerged under sub-zero seawater - it may be something in order of 30 minutes);
But if your question implies "survive without food but adequate supplies of oxygen", then the answer is:
under normal circumstances (including normal human ingenuity in finding/improvising shelter if necessary, and maintaining adequate body temperature): about four weeks.
But with unusually high levels of initial body muscle and fat reserves, ingenuity and courage/determination - it may perhaps be something in order of 40 days or thereabouts.
As long as your not gonna try it, id say a couple of days. And taking a lot of naps. It just depends on the person. And if you be thirsty!!!!
about four weeks before the body and organs start shutting down
about a month, defiantly more than a couple of days.
Just curious .
