Glycemic Index and Diabetes

The glycemic index, or GI, measures how a carbohydrate-containing food raises blood glucose.  Foods are ranked  based on how they compare to a reference food-either glucose or white bread.

A food with a high GI raises blood glucose more than a food with a medium or low GI.

Meal planning with the GI involves choosing foods that have a low or medium GI.  If eating a food with a high GI, you can combine it with low GI foods to help balance the meal.

Examples of carbohydrate-containing foods with a low GI include dried beans and legumes (like kidney beans and lentils), all non-starchy vegetables, some starchy vegetables like sweet potatoes, most fruit, and many whole grain breads and cereals (like barley, whole wheat bread, rye bread, and all-bran cereal.

Meats and fats don’t have a GI because they do not contain carbohydrate

Below are examples of foods based on their GI.

LOW GI FOODS (55 OR LESS)

* 100% stone-ground whole wheat or pumpernickel bread

* Oatmeal (rolled or steel-cut), oat bran, muesli

* Pasta, converted rice, barley, bulgar

* Sweet potato, corn, yam lima/butter beans, peas, legumes and lentils

* Most fruits, non-starchy vegetables and carrots

MEDIUM GI (56-69)

* whole wheat, rye, and pita bread

* Quick oats

* Brown, wild or basmati rice, couscous

HIGH GI (70 OR MORE)

* White bread or bagel

* Corn flakes, puffed rice, bran flakes, instant oatmeal

* Shortgrain white rice, rice pasta, macaroni and cheese from mix

* Russet potato, pumpkin

* Pretzels, rice cakes, popcorn, saltine crackers

WHAT AFFECTS THE GI OF A FOOD?

Fat and fiber tend to lower the GI of a food.  As a general rule, the more cooked or processed a food, the higher the GI; however, this is not always true.

Below are a few specific examples of other factors that can affect the GI of a food:

* Ripeness and storage time – the more ripe a fruit or vegetabe is, the higher the GI

* Processing – juice has a higher GI than whole fruit; mashed potato has a higher GI than soft-cooked pasta)

* Cooking method – how long a food is cooked (al dente pasta has a lower GI than soft-cooked pasta)

* Variety – converted long-grain white rice has a lower GI than brown rice but short-grain white rice has a higher GI than brown rice.

OTHER CONSIDERATIONS

The GI value represents the type of carbohydrate in a food but says nothing about the amount of carbohydrate typically eaten.  Portion sizes are still relevant for managing blood glucose and for losing or maintaining weight.

The GI of a food is different when eaten alone than it is when combined with other foods.  When eating a high GI food, you can combine it with other low GI foods to balance out the effect on blood glucose levels.

Many nutritious foods have a higher GI than foods with little nutritional value. For example, oatmeal has a higher GI than chocolate. Use of the GI needs to be balanced with basic nutrition principles of variety for healthful foods and moderation of foods with few nutrients.

GI OR CARBOHYDRATE COUNTING?

There is no one diet or meal plan that works for everyone with diabetes.  The important thing is to follow a meal plan that is tailored to personal preferences and lifestyle and delps achieve goals for blood glucose, cholesterol and triglycerides levels, blood pressure, and weight management.

Research shows that both the amount and the type of carbohydrate in food affect blood glucose levels. Studies show that the total amount of carbohydrate in food, in general, is a stronger predictor of blood glucose response than the GI.

Based on the research, for most people with diabetes, the first tool for managing blood glucose is some type of carb counting.

References.  American Diabetes Association  www.diabetes.org  02/06/2017