We need certain amount of calories every day. Anything you eat more than that is going to be stored in the body and you get over weight. Food provide us Nutrients - Carbohydrate, Protein, Fat, Fibers, Vitamins and Minerals. Our main source of energy is carbohydrate. Our rich source of energy is fat.
Protein makes up most of our part of the body.
To convert carbohydrate, protein and fat into energy and other compounds, we need Enzymes . Vitamins are part of our enzymes. Our body also needs small amounts of different kinds of minerals. Some in large quantity, some in traces. Calcium, Iron, Copper, Zinc, Molybdenum are all very important minerals.