Glycemic Index | by Jerry Sobieraj, MD ©2000-4 |
Your Blood Sugar
When we eat, we absorb the nutrients in our food, which ultimately leads to an increase in our blood sugar. The amount our blood sugar increases after eating depends on the type of food we eat. Early attempts to estimate the impact of food on blood sugar focussed strictly on its sugar content. However, the sugar content of a food did not consistently predict its effect on blood sugar.
In the early 1980s, controlled comparisons of food absorpiton were studied. To make these comparisons possible, a way was needed to "compare apples to apples, and oranges to oranges". The glycemic index was the result.
The Glycemic Index
The glycemic index compares the blood sugar response after eating a food in comparison to white bread or pure sugar (glucose in this case, the sugar most commonly used in your body for energy). Thus, a food that leads to a rapid blood sugar rise (e.g. white bread) is arbitrarily assigned a value of 100 (100 grams of the test food is studied so that quantities remain consistent). Foods which have glycemic indices less than 100 are less likely to cause a sharp sugar increase, while those greater than 100 actually make your blood sugar rise more rapidly than pure sugar itself.
Starches and Your Blood Sugar
Starches are the foods having the greatest range of glycemic indices. This is due to their high carbohydrate content. Carbohydrates which are rapidly digested, can lead to a sharp increase in blood sugar, when they release their sugar building blocks.
All simple sugars (e.g. glucose, fructose, galactose, etc) are found in carbohydrates. Since carbohydrates are chains of these sugars, carbohydrates can have sugar like effects. For example, the starch in potatoes is easily broken down by an enzyme in your saliva (salivary amylase). Thus, by the time the potatoes have reached your stomach, they are mostly simple sugars (i.e. glucose) or very small chains of simple sugars (i.e. 2-3 sugars linked together).
Factors in Food Affecting Glycemic Index
- The types of connections (chemical bonds) between the simple sugars in the carbohydrate chains. We are only beginning to understand how these connections influence the absorption of sugar from the intestine into the blood.
- Fat content: Fat slows the absorption of sugar, and thus, lowers the glycemic index.
- Fructose: This simple sugar is the major sweetener in fruits and vegetables. The increase in blood sugar is lower with fructose than with other sugars (fructose has a glycemic index of 27)
Food | Glycemic Index |
Breads | 50-100 |
| Pumpernickel (Rye Kernel Based) | 50-60 |
| Rye Flour Bread (American Pumpernickel) | 60-80 |
| Pita (Pocket) Bread | 50-80 |
| Whole Wheat Bread | 90-95 |
White Bread
(the reference food for these tables) | 100 |
| Bagel (Lender's) | 100 |
Breakfast Cereals | 40-125 |
| All Bran (Kellog) | 40-60 |
| Museli | 60-80 |
| Oat Bran | 60-70 |
| Special K | 70-9- |
| Grapenuts | 95 |
| Puffed Wheat | 100 |
| Golden Grahams | 100 |
| Total | 110 |
| Cheerios | 110 |
| Corn Chex | 120 |
| Rice Crispies | 120 |
| Rice Chex | 125 |
| Corn Flakes | 125 |
Grains | 30-120 |
| Barley | 30-60 |
| Bulgar (found in Tabouli) | 60-70 |
| Rice, white, long grain | 70-80 |
| Corn, Sweet | 85 |
| Couscous (Near East) | 90 |
| Cornmeal | 95 |
| Taco Shells (Old El Paso) | 70-95 |
| Rice, brown | 70-90 |
| Rice, instant | 90-120 |
Legumes | 35-70 |
| Chickpeas | 40 |
| Lentils | 30-60 |
| Kidney Beans | 40-60 |
| Lima Beans | 45 |
| Navy Beans | 55 |
| Black Eyed Peas | 60 |
| Pinto Beans | 55-65 |
| Green Peas | 50-70 |
Pasta | 60-70 |
| Capellini | 65 |
| Linguine | 65 |
| Macaroni | 65 |
| Spaghetti | 60 |
| Rice Noodles | 60-85 |
Root Vegetables | 70-120 |
| Carrots | 70 |
| Sweet Potatoes | 85 |
| Potatoes, White (Boiled) | 80-120 |
| French Fries | 105 |
| Potatoes, Russet, baked | 120 |
| Potatoes, Instant | 120 |
Baked Goods | 65-110 |
| Banana Bread | 65-75 |
| Pound Cake | 75 |
| Fruit Muffins | 65-80 |
| Oatmeal Cookies | 70-80 |
| Shortbread | 90 |
| Cheese Pizza | 90 |
| Croissant or Bagel | 100 |
| Graham Crackers | 105 |
| Doughnut | 110 |
Crackers | 90-115 |
| Rye Crisp Bread | 90 |
| Wheat Thins | 100 |
| Saltines | 105 |
| Rice Cakes | 115 |
Snack Foods | 50-105 |
| M&M Peanut | 50 |
| Milk Chocolate | 60-70 |
| Potato Chips | 80 |
| Corn Chips | 90 |
| Popcorn | 100 |
| LifeSavers | 100 |
| Tortilla Chips (Nachos) | 105 |
FRUITS: 40-80
All fruits have a low glycemic index, 40-80.
Bananas, Mangos and Raisins are on the high end (70-80). Fruit juices are ok but should be limited (as you can easily exceed 100grams). If you'd like to drink fruit juice regularly, diluting it with an equal volume of water (or sparkling water) helps to limit the calories and sugar load. Fruit Drinks are not acceptable as they have added sugar or corn syrup (which is nutritionally equivalent to sugar)..
VEGETABLES: 35-55
All non-root vegetables have a low glycemic index, 35-55. You can't eat too many vegetables.
This refers to all vegetables that are not listed above under "Roots" or "Legumes".
All Fish, Poultry, Meats, Dairy, Eggs and Nuts have LOW glycemic indices
These foods have glycemic indices less than 60.
This is due to their higher protein and fat content. However, caution may still be necessary with high fat varieties of this food group (e.g. steaks, bacon, whole milk and large quantities of nuts).
