What is the role of the body’s reserves?

Any good system must be protected from external harmful influences and have a reserve supply of substances. We have a store of fats, proteins and carbohydrates in our cells. We have body fat. Someone has it big, someone smaller. We also have a supply of water, some minerals and salts. All this stock has an important role to play. If suddenly we do not have the opportunity to eat or drink, the body uses the reserve stock. Without it, we would be dying of hunger and thirst in the literal sense, if we did not have a snack and drink in time.