We eat different types of vegetables, fruits, cereals and pulses. We all eat food to obtain energy for our daily activities. There are various components of food, and each of these components is required by our body to perform different cellular activities. What are Nutrients? Each dish is made up of one or more ingredients which we get from animals and plants. Carbohydrates act as the primary source of energy for the active brain. Protein is the main structural component of cells and helps in building the body tissue.