Carbohydrates are used as an energy source in respiration. They are also used as building blocks. Carbohydrates are made up of carbon, hydrogen and oxygen. An example is starch from potatoes
Proteins are mainly used for growth and repair of cells. Proteins are made up of carbon, hydrogen, oxygen and nitrogen. An example is protein from meat and dairy products
Vitamins and minerals are needed in small amounts. An example is calcium which we get mainly from milk. We also need vitamin C for healthy gums which is found in lemons and citrus fruits
Roughage is also needed to prevent constipation. It is not digested but adds bulk to the alimentary canal. Roughage is found in bran and brown rice.