How do you define glycemic index
The glycemic index of a food is a measure of the effect of carbohydrate on blood sugar levels. Foods that can be broken down quickly after ingestion to release glucose into the bloodstream are considered to have high GI, while foods that are broken down slowly and release glucose gradually into bloodstream are considered to have a low glycemic index. Those with diabetes , maintaining a diet made up of low GI foods has several important health benefits.
(two hour blood glucose response of required food) X 100
Glycemic index of standard food (glucose or white bread)
Glycemic load accounts for how much carbohydrates Is present in the food and how much each gram of carbohydrates raises blood glucose levels.
The glycemic load of a food is calculated by multiplying the glycemic index by the amount of carbohydrates in grams provided by a food and dividing the total by 100.Dietary glycemic load is the sum of the
glycemic load in all foods consumed in the diet.
There are a variety of factors that can account for the glycemic index of different foods, Some of which are naturally occurring, whereas others are affected in commercialization or home preparation.
- Physical form : generally , the more processed a food , the higher the GI , for example instant oatmeal has a GI of 79 whereas steel cut rolled oats has a GI of 55.
- Food combinations: when carbohydrates foods are eaten as part of meals the GI of the meal changes based on the average of all the food had (such as red beans or legumes with rice).
- Cooking time: longer cooking time may increase the glycemic impact as a food by breaking down the starch or carbohydrate and allowing it to pass through the body more quickly when consumed.
- Acidity : the more acidic a food is ( pickled food or those containing vinegar or lemon), the lower GI . for example , sourdough bread , which uses a lactobacillus or lactic acid culture as part of the leavening process, has a lower GI than white bread.
- The fibrous coat around beans , seeds and plant cell walls in whole grains acts a physical barrier , slowing access of
- digestive enzymes to break down the carbohydrate, thus whole grain and legumes have a lower GI.
- Protein/fat: adding protein or fat , which have minimal effects on glycemic
Excursions, to a high GI food will decrease the GI of that food . for example, adding cheese to a slice of bread would decrease the GI.
- Soluble fiber: by increasing the viscosity of the intestinal contents , the interaction between the starch and the digestive enzymes is slowed, resulting in slower and lower glycemic excursions .
- Eventhough fatty foods such as cheese ,ghee etc are low in GI , these cannot be included in the diet as these are high in calories and fat.
IMPACT OF GLYCEMIC INDEX
- On diabetes: the foods with lower GI enters the gastrointestinal tract at the slower rate, which reduces both the glycemic response and corresponding insulin release thus reducing the risk for post prandial hyperglycemia.
- On obesity: decreased calorie intake throughout the day after the consumption of low GI meal
- increased the cholecystokinin (CCK) release [which are partially responsible for the sending satiety signals to the brain, thus helps in weight reduction.]
- On Cardiac health: foods with low GI results in lowering LDL cholesterol and improved HDL cholesterol .
Message about glycemic index
- Choose more fruits and vegetables.
- Increase soluble fibre in diet.
- Use combination of high GI foods with low GI foods.
- Choose fewer processed foods.
GLYCEMIC INDEX VALUE OF FOODS
Cereals GI values Ragi 86 Cornflakes 81 jowar 77 wheat 72 rice 70 semolina 60 Oatmeal plain 58 Bhajra 58 corn 56 Sweet corn 55 macroni 55 Brown rice 54 musseli 50 vermicilli 35 rye 34 Roots and tubers GI values potato 70 beetroot 64 Sweet potato 61 yam 51 carrot 47 turnip 40 raddish 18 onion 15 pulses GI values Horse gram 51 Black gram 48 Green gram 48 Chick peas 33 Black eyed peas 33 Black beans 30 Kidney beans 29 lentils 29 rajmah 29 Soya bean 18 Brussel sprouts 16 vegetables GI values pumpkin 75 lettuce 16 asparagus 15 broculli 15 cauliflower 15 cucumber 15 Egg plant 15 beans 15 spinach 15 tomato 15 cabbage 15 mushroom 15 miscellaneous GI values Potato chips 54 Strawberry jam 51 jaggery 50 Lentil soup 44 Custard 43 Tomato soup 38 Mushroom soup 27 Celery soup 27 Cucumber soup 27 fructose 20 Miscellaneous GI value maltose 105 glucose 100 Fruit roll 99 Rice cake 82 pizza 80 wafers 76 French fries 75 crackers 74 honey 73 popcorn 72 Corn chips 72 bread 71 Cranberry juice 68 Whole wheat bread 67 Coca-Cola 63 Ice cream 61 Ham burger bun 61 sucrose 59 Nuts and oils seeds GI values Dates fresh 103 raisins 64 Dates dried 42 Apricots dried 31 cashew 27 peanuts 15 Ground nuts 13 Milk and milk products GI values Full fat milk 41 Yogurt whole milk 36 Semi skimmed milk 34 Skim milk 32 Chocolate milk 32 soya milk 30 whole milk 27 Low fat sweetened tyogurt 15 Plain yogurt 14
- Glycemic Index and Diabetes -American Diabetes Association
- IGNOU text book of nutrition
- Ideas for ideai diabetic care-karnataka institute of diabetes