Carbohydrates (carbs) are day to day fuel of the body. Fats are also our body fuel, but they are used by the body only when carbohydrates stores are depleted. Carbs are also part of many tissues, cell membranes, RNA, DNA  etc. But for all practical purpose, carbohydrates will be considered as fuel.

There are three different types of carbohydrates:-

(a) Simple Sugars or Monosaccharides. These sugar have only one type of molecule e.g. glucose, fructose (fruit sugar), lactose (milk sugar), etc.

(b) Mixed Sugars or Disaccharides. These sugars have two molecules e.g. Sucrose (table sugar) has one molecule each of glucose and fructose.

(c) Complex Sugars or Polysaccharides.  Polysaccharides contain multiple chain of monosaccharides eg Starch contain multiple chain of glucose molecule. Starch is a major storage form of glucose storage in nature. Complex sugars also forms fibre in our food. 

For our health point of view; glucose, fructose, starch and fiber are very important.

Important Sources of Carbohydrates in Diet

     Carbs are widespread in nature in form of starch. Cereals, pulses, potato, fruits, vegetables etc are rich in starch, in addition to other macronutrients. Fructose is found in honey and fruits. Lactose is milk sugar. Sucrose is found in sugarcane and beet root. The digestion of carbs starts in the mouth itself. On chewing bread or roti (Indian flat bread) one experiences a sweet taste, which is due to breaking up of starch present in bread to glucose, by action of enzymes present in saliva. Carbs are mainly digested in the upper part of small intestine. Only fiber remains undigested and reaches large intestine, where it is acted upon by intestinal bacteria and digested. Carbs have been darling of the nutrition world after the nutrition guidelines were promulgated in USA by FDA. As per the guidelines, 60% of our calories should come from carbs.  We will discuss the role of carbs in health and diseases in other posts.

Its important to acquaint yourself with the above terms, as these terms will be repeatedly used in further discussions on carbs and its role in health. In next article glucose metabolism will be discussed.