Posted In: Biology

Metabolism is the process by which food is converted into energy by our body. Metabolism in Greek means ‘change’ and it refers to the transformation that take place in the cell of living organisms. Metabolism takes place within each cell of living organisms. In this process, the cells break down large molecules to release energy.

What is metabolism and how does it work?
Metabolism consists of both ‘Catabolism’ and ‘anabolism’.  Catabolism is the process in which large molecules are broken down into smaller ones and energy is released. Anabolism on the other hand results in the storage of energy. In this process, small molecules are assembled to create large molecules and energy is stored in them.

Metabolism Process | Image source:

Cells must balance the catabolism and anabolism processes so as to make sure that sufficient energy is available for the body to perform its functions. If we do not eat enough, then the cells will have to synthesize glucose from other material or when eating too much the excessive sugar is converted into storage forms like fat. Both these conditions are harmful to our body.

The metabolism process is constant and it continues throughout our lifetime. It is a very important process necessary to sustain life.

How does it work
Here is a step by step description of the metabolism process.

  • When we eat, the food enters the digestive system. Here enzymes act upon the food and break down fats into fatty acids, proteins present in the food into amino acids carbohydrates into sugars such as glucose.
  • This sugar and acids are then absorbed in the blood by the circulatory system. The circulatory system carries these products of the digestive system to the cells of the body.
  • In the cells, other enzymes act upon these compounds resulting in chemical reactions. As a result of these chemical reactions, energy is released from these compounds.
  • This energy is available for use by the body or it can be stored in body tissues for later use. If not used, it results in body fat.

Thus metabolism determines how easily our body can lose or gain weight. When energy is stored for a long time as body fat it leads to weight gain. A calorie is the unit of energy provided by a food product. Different foods have different amounts of calories. Sports persons and people living active lifestyles need a high calorie diet. When we exercise, our body burns calories.

Did you know: BMR is the Basal Metabolic rate that is the rate at which a person’s body burns energy.

BMR varies from person to person and plays a key role in a person’s tendency to gain weight.

Metabolic diseases
A metabolic disorder is caused when the chemical reactions involved in metabolism are not normal. For example, there could be abnormal levels of enzymes. This can cause buildup of toxic substances or alternatively a lack of essential substances needed by the body to function normally. Metabolic disorders can lead to various diseases. Some common conditions include:

  • Hyperthyroidism - this is caused by a hyperactive thyroid gland leading to weight loss and a swelling in the neck
  • Hypothyroidism - this is the scenario where the thyroid gland is underactive. Common symptoms are tiredness and weight gain. If left untreated, this can lead to serious development problems in children.
  • Diabetes - Type 1 and Type 2. This disease occurs when the pancreas are unable to produce sufficient levels of insulin. Over a period of time, diabetes can lead to nerve damage, kidney problems and heart disease.

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