What is Metabolism?

The body gets the energy it needs from food through a process called metabolism. Metabolism means transformation. Metabolism is a collection of chemical reactions that takes place to transform the food we eat into the energy needed by the body to perform actions. Metabolism is a constant process that begins when we're conceived and ends when we die. It is a necessary function that allows our bodies to use food and other resources to maintain the working parts, repair damage, heal injury and rid the body of toxins. Apart from aiding in digestion Metabolism aids absorption of nutrients. The metabolic activity is mostly influenced by the nutrition intake, adequate hydration and physical activity. When any one of these is lacking, the metabolic rate decreases.
After we consume food, the molecules in the digestive system called enzymes break proteins down into amino acids, fats into fatty acids, and carbohydrates into simple sugars. These compounds are absorbed into the blood, which transports them to the cells. After they enter the cells, other enzymes act to speed up or regulate the chemical reactions involved with "metabolizing" these compounds. During these processes, the energy from these compounds can be released for use by the body or stored in body tissues, especially the liver, muscles, and body fat. In this way, the process of metabolism is really a balancing act involving two kinds of activities that go on at the same time - the building up of body tissues and energy stores and the breaking down of body tissues and energy stores to generate more fuel for body functions.

Metabolism is a complicated chemical process. A calorie is a unit that measures how much energy a particular food provides to the body. The body stores the energy initially in form of fat. If a person consumes too many calories and his physical activity is not enough to utilise the consumed amount the excess remains as fat in the body thus resulting in increase of weight. The basal metabolic rate, or BMR, is a measure of the rate at which a person's body "burns" energy, in the form of calories, while at rest. Low calorie dieting slows your metabolism, making it progressively more difficult to lose weight and keep it off.

Anabolism or constructive metabolism, supports the growth of new cells, the maintenance of body tissues, and the storage of energy for use in the future. During anabolism, small molecules are changed into larger, more complex molecules of carbohydrate, protein, and fat.

Catabolism or destructive metabolism, is the process that produces the energy required for all activity in the cells. In this process, cells break down large molecules to release energy. This energy release provides fuel for anabolism, heats the body, and enables the muscles to contract and the body to move. As complex chemical units are broken down into more simple substances, the waste products released in the process of catabolism are removed from the body through the skin, kidneys, lungs, and intestines.

Several of the hormones of the endocrine system are involved in controlling the rate and direction of metabolism. Thyroxine , a hormone produced and released by the thyroid gland, plays a key role in determining how fast or slow the chemical reactions of metabolism proceed in a person's body.

The pancreas secretes hormones that help determine whether the body's main metabolic activity at a particular time will be anabolic or catabolic. For example, after eating a meal, usually more anabolic activity occurs because eating increases the level of glucose - the body's most important fuel - in the blood. The pancreas senses this increased level of glucose and releases the hormone insulin , which signals cells to increase their anabolic activities.

Metabolic disorder is caused by an abnormal chemical reaction in the body's cells. Some metabolic diseases are inherited. These conditions are called inborn errors of metabolism.