MadaraKyou is right, the current threshold for starvation or thirst notifications is just too low.
I think what we need is more accurate data about current starvation/thirst values: percentile (Food: 28%) or numeric (Food: 288/1000) values somewhere in UI will do the job and will allow decent testing of this feature. Right now we just don't know the exact values and if there is some bugs with food or drinks - there is just no way to know for sure, as there is no data available to us in game.