The ability of the food item to raise the blood sugar is measured in terms of Glycaemic Index. Glycaemic Index is a number associated with a particular type of food which gives you an idea about how fast your body converts the carbohydrate in a food into glucose. A value of 100 which is an equivalent amount of pure glucose represents the standard.
Different foods having the same amount of carbohydrates can have different Glycaemic Index numbers. Foods containing simple Carbs that release glucose rapidly into the bloodstream tend to have a high GI whereas foods with carbohydrates that take long time to break down and, release glucose more gradually into the bloodstream, tend to have a low GI.
FACTORS AFFECTING GLYCAEMIC INDEX:
Glycaemic Index of food depends on many factors. Same food may have different Glycaemic Index depending on following factors.
Ripeness and storage time: The process of ripening of a fruit or a vegetable increases Glycaemic Index of the fruit or a vegetable.
Processing: Glycaemic Index of food changes after processing. eg. fruit juice has higher GI than whole fruit; bread prepared from refined wheat flour has higher GI than that of a whole wheat bread.
Cooking method: Glycaemic response is higher with cooked food when compared with raw food.Overcooking or more the cooking, higher is the GI.
Other food you eat: The food’s effect on a person’s blood glucose level varies if the food is combined with other food rather than eating alone. It is always good to consume a Low GI food when a high GI food is consumed. Nutrients like fat, fibre, protein influence GI as they affect the rapidity of absorption.
Depending on the GI of food, foods are categorized into:
Low GI Foods (0-55)
Medium GI Foods (56-70)
High GI Foods (70+)
Some of the foods with their Glycaemic Index are mentioned here.
Millets 71 Black Gram 48
Bread 70 Apple 39
Rice (White) 72 Banana 69
Wheat 70 Orange 40
Soy Beans 43 Potato 70
Rajmah 29 Sweet Potato 48
Bengal Gram 47 Yam 51
Green Gram 48 Beetroot 64
Source:B. Srilakshmi; 2003;Dietetics.,4:267