There are several things in Uninhabited a player needs in order to stay alive.
The best way of getting food is by killing a pig using a Hunting Knife (Crafted - Stick + Stone plate). The second way to feed yourself is by eating berries, however they are less filling.
When playing the game, you will find that you get thirsty a lot faster than hungry. Collecting water in a water bucket (Crafted Wood Plate + Stick ) although it is difficult to get a bucket on your first day. An alternative, although far less reliable and efficient, is by eating berries.
Heat and ColdEdit
Players will die of heat if they wear warm clothes while near fire, if they are too close to multiple fire sources etc. The best way to avoid this is simply by unequipping your torch and moving away from fire if the screen turns orange.
Cold is a big killer. At night, the map becomes too cold to survive in. (This is a flaw in the game, as it is impossible for players who spawn at night to survive). The only way to survive this is by wearing bear fur clothes or by standing near (But not on!) a fire.
If a player goes in water deeper than their head, their screen will start to turn blue. If they stay in the water they die