Metabolism is term used for all of physical and chemical reactions in body. The chemical reactions of metabolism take food we eat and transform it into fuels and building blocks for body. These chemical reactions are necessary for providing energy for activities such as movement and thinking, and for organ function such as digestion, and formation of urine. These reactions are also critical for breaking down old tissue and building new tissue.

The foods that we consume are chemically complex. They must be broken down by body into simpler chemical forms called nutrients. Nutrients are taken in through intestinal walls and transported by blood to cells. The processes involved are called digestion, absorption, and metabolism.

Digestion begins process through a series of physical and chemical changes by breaking down food in preparation for absorption from intestinal tract into bloodstream. Digestion actually begins when chewing breaks large pieces of food into smaller pieces.

The next step in this process is absorption. Absorption takes place primarily in small intestine, where its surface area is comparable to a quarter of a football field and its length is 20 feet. That's pretty amazing, isn't it?

Nutrients are taken up by intestines and passed into bloodstream to facilitate cell metabolism. Within 3 to 4 hours after a meal has been eaten, body must find a way to absorb millions of nutrient molecules including amino acids (proteins), monosaccharides, monoglycerides, glycerol (carbohydrates), fatty acids and glycerol (fats), vitamins, and minerals.

A whole lot of stuff goes on here, with villi (several hundred cells covered with microscopic hairs) in constant motion, trapping nutrient molecules and digesting and absorbing them into cells.

By time we get to metabolism, handling of food within body has reached its final stage. The process of metabolism involves all chemical changes that nutrients undergo from time they are absorbed until they become part of body or are excreted from body. Metabolism is conversion of digested nutrients into components for energy or for building material for living tissue.

A diet high in fats has been recognized as a primary villain and risk factor in cardiovascular disease. The difficulty many people have in understanding risk of a high fat diet is not so much in total fat but in types of fat included in diet. On one hand there are two types of fats - one of which is good, one of which is bad. Saturated fats are one of villains when it comes to bad fat part of formula and this type of fat is commonly found in almost all foods. Unsaturated fats are far less harmful. It is recognized that approximately 95 percent of population is deficient in essential fatty acids.

Essential fatty acids are involved in energy production, transfer of oxygen from air to bloodstream, and manufacture of hemoglobin. They are also involved in growth, cell division and nerve function. Essential fatty acids are found in high concentrations in brain and are essential for normal nerve impulse transmission and brain function.

Essential fatty acids are also involved in manufacture of prostaglandins, substances which play a role in a number of body functions including hormone synthesis, immune function, regulation of response to pain and inflammation, blood vessel constriction, and other heart and lung functions.