While i like the concept as it adds tension and can become a real issue, im having a hard time getting around the narration of it.
If a character carefully packs and rations her food (etc), i cant really see how it could potentially run out the first day without warning.
Similarily, another character only has a single ration but somehow makes it last for over a week.
In forbidden lands, which is kind of a goofy game to begin with, i think its fine, but the more serious and more sensible nature of Alien makes it feel out of place.
Also, is it correct that you can lose more than one amount each time you check or is it a mistake? (Lose one level per 1 rolled). In theory a person carrying the max number of rations (6) can lose them all the first day, while the one with a single ration can last for days and weeks.