How do carbohydrates spare protein?

This is a so-called role or function of carbohydrate in the body. However, it is incorrect to attribute action (other than chemical action) to carbohydrates or other inanimate substances. Besides, "sparing protein" is not a function or role of carbohydrates at all. Carbohydrates simply furnish our fuel or energy needs-and nothing more.

What is being said in the textbooks is that proteins consumed will be used for tissue building and maintenance rather than being used as an emergency source of energy as long as the carbohydrate intake is sufficient. This is true, but it is only another way of saying that carbohydrates are the primary and most efficient source of energy or fuel and that it is best not to try to meet our fuel needs from proteins. It is stating the true fact that carbohydrates, not proteins, supply our primary nutrient needs.

"Sparing proteins" is not a separate and distinct function or role of carbohydrates any more than preventing scurvy is a separate and distinct function of vitamin C in the body. Vitamin C supplies body needs, but its role is not prevention of scurvy or of anything else. Viewing nutrients as preventative agents of diseases is another way of saying that diseases are normal, that they are an inevitable part of life that will and must occur unless prevented by the proper nutrients. That is a backwards way of viewing health-it's the disease approach, or the medical approach. Just as good things happen to us if we think positive thoughts and visualize success, harmony, etc., good health will exist as long as we live healthfully-and that includes consuming the correct amounts of the foods to which we were biologically adapted in nature to eat.

In short, the so-called "protein-sparing action" of carbohydrates is not only not an action, but sparing proteins is not a distinct role of carbohydrates separate from their energy-providing role.