Carbohydrates form the major source of energy in Indian diets. The quantity and quality of dietary carbohydrates are important as carbohydrates with high glycaemic index (GI) and glycaemic load (GL) have been found to be associated with the risk of non-communicable diseases. Indian culinary preparations are diverse region specific with unique carbohydrate profile and glycaemic properties. In addition, carbohydrate constituents in different foods may undergo modification/transformation during processing/food preparation, all of which could synergistically determine post-meal glycaemic response to the food.
Physiologically, dietary carbohydrates are broadly classified as available (glycaemic carbohydrates, which are metabolizable and raise the blood glucose upon consumption) and unavailable carbohydrates (which are not digested and may get fermented in the colon). Most of the dietary fibres and resistant starch (RS) are unavailable carbohydrates. The glycaemic property (carbohydrate quality) of a food is assessed by the GI, a relative ranking system, which classifies carbohydrate-containing foods based on their ability to raise blood glucose levels upon ingestion as against reference food (glucose). This GI system has been recommended for making healthier carbohydrate food choices by the Food and Agriculture Organization (FAO). Glycaemic response of foods is dependent on a multitude of factors such as food form, composition (nature and content of carbohydrates, presence of RS, dietary fibre, protein and fat), method of preparation and processing, and is unique for each food. RS, presents in some of the foods or formed during processing, is resistant to digestion by digestive enzymes and may help in reducing the glycaemic response and glycaemic load (GL) of diets and also in improving insulin sensitivity.