Foods are classified based on their different aspects like the quantity needed, the functions they serve etc. Based on the quantit y and the large functions they are categorized into macro or energy foods and micro foods. The energy foods are further divided into carbohydrates, proteins, and fats. Carbohydrates form the bulk of food and contributor of energy. Proteins, on the other hand, are more for repairs and reconstruction of the body tissues. Fat plays slightly more complicated role. It has the highest energy density. They act as a solvent for many oil soluble micronutrients. It also plays a part in making many chemicals in the body.

Carbohydrates : Carbohydrates are compounds formed by carbon, hydrogen and oxygen molecules. The simplest is monosaccharides. They are very easily digested and assimilated into the bloodstream raising the glucose levels very quickly. They are burned up also fast providing a quick spurt of energy. The second is disaccharides, normally, an intermediary during the digestion of trisaccharides or complex starches. Trisaccharides or polysaccharides are difficult to digest. These are complex molecules and the body takes the time to break them. Hence, they do not raise but maintains a steady blood sugar level and it takes longer to feel hungry.

Proteins :

Fats : Fats are esters or products of neutralization of fatty acids with glycol. Their structures are quite complex. The simplest is a monomer growing into bigger polymers. Another important factor in fats is the amount of hydrogen in them. The amount of hydrogen in a molecule of fat is measured by its saturation. If one starts to knock of hydrogen atoms from fats they become unsaturated. A saturated fat is solid at ordinary room temperatures and is more difficult to digest and not considered good for our body. However, all fats that are solid at ordinary temperatures are not bad for the body, the example is coconut oil which is considered good. What matters is the straight length of their molecules. Longer ones are not good for the body.

Micronutrients : Micronutrients are mostly mineral salts. In the body , they exist as ions. They are sodium, potassium, calcium, iron , iodine manganese, magnesium, zinc, selenium. Molybdenum and chloride. All these are obtained if one eats a well-balanced diet on a regular basis.