if you're going to be away for hours, like overnight, the BEST thing is to pause the game if you're worried that the little guys might starve to death -

it gets tricky when you're trying to accumulate tech points so you can upgrade skills while avoiding having the food run out - for what it's worth, I've had one game now running for 270 hours after killing off about 3 or 4 villages and just abandoning a couple of games where one of the original settlers died overnight.

good luck!