Carbohydrates as it Relates to Metabolism

Carbohydrates as it Relates to Metabolism



To understand metabolism, we have to understand how our body uses and stores energy. The cells of our body metabolize energy, which is obtained from the protein, carbohydrates, and fats that we eat as foods. These energy sources come in various forms, and these different forms of energy affect our metabolism. While all the categories of food are important for the body to function, the proportion in which we need to take these is still a topic for hot debate.


Nevertheless, carbohydrates is the most important source of energy for any activity that we do. Once we eat carbohydrates, it is further broken down to smaller sugars like glucose, fructose and galactose. These sugars get absorbed and are used as energy. The glucose that is not used immediately gets stored in the muscles and the liver in the form of glycogen. Once this glycogen store is saturated, all extra glycogen gets stored as fat.


Glycogen is the source of energy for almost all types of exercise – whether it is for short runs or for extended sports by athletes. Weight lifting, swimming, climbing, and all other forms of exercise needs glycogen for energy.


The right amount of carbohydrate is necessary in our metabolic processes as it prevents protein from being used as energy. If you do not take adequate amount of carbohydrates, the protein will break down to make glucose for energy. Since the primary function of proteins is to build muscles, bone, skin, hair and other tissues, then you are naturally limiting your resources for building and maintaining tissues if you rely on it for energy source.  Eating fewer carbohydrates also puts an extra load on the kidneys, which has to work double time to eliminate the waste from protein breakdown.


It is interesting to note that one gram of carbohydrate provides 4 calories of energy. Our muscles store carbohydrates; you will often hear a sports person talking about carbohydrate loading and depletion, which refers to the amount of carbohydrate energy we can store in our muscles.


Though this is around 2000 carbohydrate calories, we can alter this amount through depletion or supplementation. Carbohydrates can be simple or complex forms. Simple carbohydrates are converted to energy very quickly and can provide a fast source of energy.


Fruits and energy drinks are good examples of simple carbohydrates. Complex carbohydrates take longer time to be metabolized and absorbed in the body. They also take a long time to be broken down. Pasta, rice and breads are good examples of complex carbohydrates. Starch and fiber are also examples of complex carbohydrates, but fibers cannot be digested and used as an energy source.

Foods high in starch include pasta, cereals and whole grains. The diseases which occur due to defect in carbohydrate metabolism include: Diabetes mellitus, Lactose intolerance, Fructose intolerance, and Galactosemia and Glycogen storage disease