This applies to 2 scenarios

1. You have food/water, but not enough to go trough the day without going hungry/thirsty (like stomach growling and stuff), but generally you are not at risk of starvation or dehydratation.

2. You have food/water, but when you run out, you are in trouble.

My question includes - how often do you eat/drink your limited amount of food/water to A. Survive at all cost, B. Go trough the day without your stomach growling or being unconfortable, C. Using your food to give the best performace before running out.

It's a bit strange and dumb scenario but's it's been on my mind for a while and where else can I ask this right?