Food biochemistry is concerned with the breakdown of food in the cell as a source of energy. Each cell is a factory that converts the nutrients of the food one eats to energy and other structural components of the body. The amount of energy that these nutrients supply is expressed in Calories (kilocalories). The number of Calories consumed will determine the energy balance of the individual and whether one loses or gains weight. The nutrients come in a variety of forms, but they can be divided into three major categories: carbohydrates, lipids (fats), and proteins. These nutrients are broken down by the cell metabolically to produce energy for cellular processes. Other components are used by the cell and the entire body for structure and transport. Each of these nutrients is essential to a well-balanced diet and good health. Two other components of a successful diet are vitamins and minerals.