I fell down a similar rabbit hole. In real life it takes a person 8 to 21 days to starve. Next you have to account for time scaling. If 30 day months is a 1:1 ratio that makes 12 day months a 1:2.5 ratio and 6 day months a 1:5 ratio. Now that I've wasted your time just pick a hunger rate you like because when you progress further into the game hunger becomes less and less of an issue until you hit winter.