What is The Glycemic Index?

The glycemic index (GI) rates foods by how much they raise blood glucose. Candy, sugar, cake, and cookies have a high GI, while whole-grains, certain starchy vegetables and fruits, have a lower GI. Carbohydrates with a low GI value (55 or less) are more slowly digested, absorbed, and metabolised. They typically cause a lower and slower rise in blood glucose and, therefore usually, insulin levels.

Since it’s the carbohydrates in food that raise blood sugar, the glycemic index can help when trying to figure out which foods are the best for you. Since all carbohydrates don’t affect blood glucose levels the same way, knowing which carbohydrates have a lower glycemic index can help you plan your meals more effectively.

Most foods have a range of GI numbers, depending on many factors; sometimes how long a food is cooked can influence the GI. For example, when pasta is cooked “al dente,” the GI is lower than if it is cooked longer. Also, the composition and the order in which you eat your food can affect how rapidly the blood sugar rises. Studies have shown that eating fat and protein prior to carbohydrate can slow the absorption of the carbs.

What’s Good Way to Determine Which Foods Work Best For You?

A good way to assess how your body is affected by certain foods is to test your blood sugar two hours after a meal. For most people an ideal blood sugar result will be less than 140mg/dl two hours after the start of a meal. If you are not sure of what your target blood sugar should be, discuss it with your physician.

To help you understand how the foods you are eating might impact your blood glucose level, here is an abbreviated chart of the glycemic index for some common foods. A more complete glycemic index can be found online.

FOODGlycemic index (glucose = 100)
White wheat bread*75 ± 2
Whole wheat/whole meal bread74 ± 2
Specialty grain bread53 ± 2
Unleavened wheat bread70 ± 5
Wheat roti62 ± 3
Chapatti52 ± 4
Corn tortilla46 ± 4
White rice, boiled*73 ± 4
Brown rice, boiled68 ± 4
Barley28 ± 2
Sweet corn52 ± 5
Spaghetti, white49 ± 2
Spaghetti, whole meal48 ± 5
Rice noodles†53 ± 7
Udon noodles55 ± 7
Couscous†65 ± 4
Cornflakes81 ± 6
Wheat flake biscuits69 ± 2
Porridge, rolled oats55 ± 2
Instant oat porridge79 ± 3
Rice porridge/congee78 ± 9
Millet porridge67 ± 5
Muesli57 ± 2
Apple, raw†36 ± 2
Orange, raw†43 ± 3
Banana, raw†51 ± 3
Pineapple, raw59 ± 8
Mango, raw†51 ± 5
Watermelon, raw76 ± 4
Dates, raw42 ± 4
Peaches, canned†43 ± 5
Strawberry jam/jelly49 ± 3
Apple juice41 ± 2
Orange juice50 ± 2
Potato, boiled78 ± 4
Potato, instant mash87 ± 3
Potato, french fries63 ± 5
Carrots, boiled39 ± 4
Sweet potato, boiled63 ± 6
Pumpkin, boiled64 ± 7
Plantain/green banana55 ± 6
Taro, boiled53 ± 2
Vegetable soup48 ± 5
Milk, full fat39 ± 3
Milk, skim37 ± 4
Ice cream51 ± 3
Yogurt, fruit41 ± 2
Soy milk34 ± 4
Rice milk86 ± 7
Chickpeas28 ± 9
Kidney beans24 ± 4
Lentils32 ± 5
Soy beans16 ± 1
Chocolate40 ± 3
Popcorn65 ± 5
Potato crisps56 ± 3
Soft drink/soda59 ± 3
Rice crackers/crisps87 ± 2

When your blood sugar spikes after a meal above normal levels, it can trigger inflammation inside your blood vessels, which can lead to heart attack and death. One study revealed that if the post-prandial blood sugar consistently was above 140, there was a two-fold incidence in death due to heart disease.

Improvements in diet can exert a profound effect on this inflammatory effect. Low glycemic index vegetables, small amounts of whole fruit, nuts, lean protein, fish oil, caloric restriction, weight loss and low to moderate use of alcohol improve post meal blood sugar and it’s resulting inflammatory affect.