Glycemic Index and Glycemic Load


Glycemic index and glycemic load are important factors that diabetic patients and patients with risk of having diabetes should apply in their daily selection of carbohydrate food. Food with lower glycemic index are good choice. Glycemic index is a number from 0 to 100 assigned to a food, with reference to pure glucose, ( given the value of 100 ) which represents the relative rise in the blood glucose level two hours after consuming that food. It rates carbohydrates according to how quickly they are broken down and release glucose during digestion.


Food with low Glycemic Index breakdown slowly and release glucose gradually while food with high Glycemic Index breakdown fast and release glucose quickly


GI is useful for quantifying the relative rapidity with which body breakdown carbohydrates. Individual response vary greatly. GI diet or slow carb diet also help in losing extra bodyweight. Low GI food prolong food digestion due to their slow breakdown and may help in feeling full hence decreasing appetite.


GI values are calculated after a research on carbohydrates. They are generally divided into three categories:

  • Low Glycemic Index : less than 55
  • Medium Glycemic index : 56-69
  • High Glycemic index : 70 and higher

Low Glycemic index food e.g. soy products, beans, fruits, milk, pasta, grain bread, oats and lentils.

Medium Glycemic index food e. g. Orange juice, honey, brown rice, wholemeal bread.

High Glycemic index food e. g. Potatoes and white bread.

Comparing these values help in making healthier food choices.

One drawback is that values do not relate to serving quantity. A food with low glycemic index can have a high carbohydrate content. For example a watermelon has GI value of 80, but typical serving is much smaller. To account for these glycemic load is calculated, that is glycemic index in a typical serving. For example a 120 g or 3/4th cup of watermelon has a GL value of 5.


Glycemic load

Glycemic load ( GL) takes into account the amount of carbohydrate in a portion of food together with how quickly it raises blood glucose level. It helps to workout how different sized portions of different food compare with each other in terms of their blood glucose raising effect. For example even though pasta has low GI, a large serving still make blood sugar high.


Glycemic load can be workout by a formula:

GL = GI × g of Carbohydrate per serving /100

For example GI of wheat pasta is 43. The CHO content of a standard 180g serving is 44 g.

So GL = 43 × 44 ÷ 100 = 19g

The GL values are grouped into:

  • Low Glycemic Load : 1-10
  • Medium Glycemic Load: 11-19
  • High Glycemic Load : 20 or more

The GL value of any food is affected by several factors, that is how food is cooked or processed. Secondly it do not tell other food nutritional information. For example whole milk has GL value of 4 but it has fats too so not a very good choice for losing weight. Knowing the glycemic load is helpful meal planning tool. For optimal health, The Glycemic Index Foundation recommends keeping your daily glycemic load under 100.


Foods with low glycemic load of 10 or less

  • 8 oz skimmed milk ( GL- 4)
  • 1/4 cup peanuts (GL-1)
  • 2 cups watermelon (GL-4. 3)
  • 1 cup kidney beans (GL-7)
  • 1cup bran cereal (GL-9)

Food with medium Glycemic load of 11-19

  • One large banana. (GL-12. 4)
  • 1cup cooked oatmeal GL-11.7)
  • 1 medium doughnut (GL-17)
  • One cup boiled brown rice (GL-18)
  • 1 tablespoon of honey (GL-11.9)

Food with a high glycemic load of 20 or more

  • 1 cup cornflakes (GL-21)
  • 2tablespoon of raisin (GL-27. 3)
  • 1 medium baked russet potato (GL-23)

On packaged food, you can find total carbohydrate grams on the Nutrition Facts label. You can also check this in a list or use a carb-counting calculator. Divide the weight of food in grams by 100 then multiply this figure by the carb per 100g. This will give the amount of carb. Consuming  carbohydrates with low GI and calculating the number of grams of carbohydrates would produce the most stable blood sugar. It is useful for diabetic people to assess which quantities of which food are likely to be suitable for maintaining good blood glucose level. Assessing the glycemic load of food can be particularly helpful if you have a specific meal quite often or you want to try another meal but are not sure how it will impact on your blood sugar.


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