As far as the body is concerned, food is made of various nutrients, and a large number of substances that have no nutrient value. Nutrients are the materials the body needs to build itself and stay in top working order. Some of these nutrients—primarily carbohydrates and fats, but also protein—provide energy. Others—protein and minerals—are building materials. Still others—vitamins and some trace elements and fatty acids—are necessary for the chemical reactions that produce energy to move muscles or carry out the regulation of body metabolism. To operate at its best, the body needs these nutrients in the right amounts. Too much or too little can—and often does—result in the body dysfunctioning. That's what we know as disease.
Understanding what food is made of is important if you are to provide your body with the right balance of nutrients. But you do not have to know every last detail of the nutritional composition of your food, or even the biochemical