Protein, carbohydrate, and fat are known as macronutrients (macro is from the Greek makros, meaning big or long.) Micronutrients, which include vitamins, minerals, and trace elements, are also important dietary components. A third category is non-nutritive components, which include fiber, water, additives, and a multitude of chemicals in plants and animals, some of which have yet to be identified.

Nearly all foods contain a combination of two or three of the macronutrients. The exceptions are foods like butter, oil, lard, and shortening, which are 100 percent fat, and honey and sugar, which are 100 percent carbohydrate.

Following the basic principles of moderation, variety, and balance, the ideal diet provides all the nutrients needed for life. With adequate amounts of protein, carbohydrate, fat, vitamins, and minerals, you will have nourishment for growth and replacement of bone, muscle, and other tissues. You will have enough energy for daily living and plenty left over for exercise.

Most of us eat at least twice as much protein as we need. Generally, a high-protein diet is recommended only in special circumstances, as for example when someone is recovering from illness, severe burns, or other accidents. Proteins are made up of amino acids. When dietary protein from plant or animal sources is converted to body protein, amino acids provide basic components of cells and tissues, serve as catalysts for biochemical reactions, and bolster the immune system.