What would we do without water – nothing!  Out of the six classes of nutrients (water, carbohydrates, protein, fat, vitamins and minerals) water is undoubtedly the most important nutrient of all.  Our bodies cannot store water or make it on its own and each day it must be replaced as we constantly lose water through our urine, feces, sweat, skin and lungs.  Most of us could go for weeks without eating food but would last only a few days without water.