It takes about three hours to drop dead of thirst, a few more to drop dead of hunger. For a real active person in a standard (74°F 45% humidity) climate, it takes around three days to die of dehydration and thirty to die of starvation. If we match real-time to in-game time, in-game time moves 120 times faster despite gravity and orbital velocities in-game closely matching what we observe in real-life, and despite everything happening in real-time. I'll be frank: I fast for 20 hours, eat for 4, every day and if a system like this was representative I'd be dead several thousand times over. One may say our rapid hunger & thirst depletion is due to how physically active we are in-game, but refer to what's named the 'workout paradox' for why that's not necessarily correct. It'd be ideal if hunger and thirst were lengthened to better fit immersion, and make room for questionable time-consuming mechanics such as toilets and replacing life support filters. Edit: https://pmc.ncbi.nlm.nih.gov/articles/PMC3021434/ is the meta-analysis on the workout paradox. Indeed, calorie expenditure doesn't differ significantly between active and inactive groups, or those with obesity and without. It makes sense, too; why would natural selection favor a system that has a harder time feeding itself if it misses a meal? Edit #2: Okay, so here's a response in the OP for some common responses I see. I admit, it's not fair to expect people to read my replies. "It's easy to eat/drink" is not a defense. If it's easy to negate the mechanic entirely, it's a minor time tax until it becomes a major one because of how unstable the game is. When you're having issues moving your Cruz/Vestal from one inventory to another, or it doesn't want to go into your hand, or it disappears completely, it becomes more than a slight annoyance. "It rewards preparation" would be a great dunk, if exploration was in the game and/or the game was stable enough state for preparation to mean anything. As-is, you 'prepare' for a long duration outside a station and fall into the planet and die, or your ship clips into the station landing pad and explodes. "You must be wearing heavy armor" is plainly false; I stick with the Odyssey 2 flight suit w/ a MacFlex Core whether I'm doing bunkers or mining. Yes, you still die of dehydration if you idle for three hours doing nothing in that armor. "it actually makes sense that we use so much energy/water running around naked" is false, see the above segment on the 'workout paradox' - the idea you can't survive a day without water in the Sahara, or a few days without food, or start to suffer serious malnutrition after a week, is a Western misconception. "You just don't like the difficulty" is missing the point - the OP's centered on how silly and immersion-breaking, and not how difficult, it is. The most generous assumption here is a misunderstanding, but I'm inclined to believe anyone saying this can't defend the mechanic so they default to character assassination. "It's supposed to be a hardcore management sim" is incorrect, it is not.