Next nutrient is protein. It is made up of nitrogen, carbon, hydrogen, oxygen, Sulphur and Phosphorus. It is known as a body building nutrient because it is the main constituent of our tissues. It supplies the amino acids to cells for the continuous replacement of cells throughout life.
Proteins supply raw materials for the body to synthesize enzymes like trypsin and pepsin. It is also an alternative source of energy when carbohydrates and fat are insufficient. One gram of protein produces four calories of energy.
Sources of proteins include meat, fish, poultry, eggs, milk and milk products. Cereals, grains and legumes are also sources of protein. Animal sources are superior because they have the eight essential amino acids.
Excess protein can also lead to excess calories which might be stored up as fat in the body.