When we feel thirsty and have nothing to drink, we may suffer so much that we can think of nothing else. All of us have the experience of being thirsty at times—but can you imagine how it would feel to be thirsty for days and days? If a human being has absolutely nothing to drink for three weeks, he will die. Our body simply needs to replenish its liquid supply—and yet between 50 and 60 per cent of our weight is water! As a matter of fact, in the course of a day the average adult loses about two-thirds of a liter of water through perspiration, and excretes about a liter of water to get rid of waste products. On the other hand, whether we drink or not, we also take in water. When the body digests food, it obtains almost a third of a liter of liquid from this food per day. But this process of losing water and gaining it isn’t enough to keep the balance of water our body needs. Thirst is the signal our body gives us that it needs more water. Dryness in the mouth or throat is not what causes thirst, as many people believe.
