They contain 9 calories per gram and are an excellent source of energy. It is essential to have fat in our diet for cell structure, shock absorption, and heat preservation. Fat is also essential for producing fatty acids and carrying fat soluble vitamins. Fats can be categorized according to their degree of saturation. Generally, saturated fats increase blood cholesterol level whereas unsaturated fats do the opposite.
Protein is the body's building block.
It is used to build and repair tissues such as muscle, blood, internal organs, skin, hair, nail and bone. It helps maintain the body's natural fluid balance through hormones, enzymes and antibodies. Meats, milk and dairy products are the richest sources of protein, however one can also obtain protein from nuts, beans, whole grains and vegetables. Their job is to make sure other nutrients are digested, absorbed, metabolized or excreted. So, while vitamins do not provide the body with any energy, they are essential in maintaining one's metabolism, growth, and body development.