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A diabetic’s GI

/ 12:20 AM January 23, 2016


Every diabetic must be familiar with glycemic index or GI of commonly available foods and drinks, since this knowledge can come in handy to keep one’s blood sugar under control with the help of diet; and to rapidly increase it also in the event he/she feels symptoms of low blood sugar levels or hypoglycemia which can be triggered by some antidiabetic medications.

So most of the time, a diabetic should eat low-GI foods. But occasionally, high-GI foods may be taken to correct hypoglycemia immediately before serious and potentially life-threatening complications set in. Combination of high-GI  and low-GI foods may also be tried for a better-balanced and nutritious meal.


Each food usually has a GI score, such that less than 55 is considered low GI; 56 to 69 is moderate GI; and a score of 70 or higher is high GI.


The following are examples of carbohydrate-containing foods with a low GI: nonstarchy vegetables, most fruits, dried beans, legumes (kidney beans and lentils), sweet potato, corn, yam, whole grain breads and cereals (whole wheat bread, rye bread, oatmeal and all-bran cereals).

Wheat, rye and pita bread, quick oats, and brown rice have median or moderate GI.

White bread or bagel, corn flakes, puffed rice, bran flakes, instant oatmeal, short-grain white rice, rice pasta, macaroni and cheese, pumpkin, pretzels, rice cakes, popcorn, saltine crackers, some fruits like melons and pineapple are examples of high-GI foods.

Since meat and fats don’t contain carbohydrates, they don’t have a GI score.

Generally, a high-fiber diet has a relatively lower GI. Processing of foods tends to increase its GI, such that juices have a much higher GI than whole fruit, and mashed potato has a higher GI than whole baked potato. More ripe fruits have a relatively higher GI, too.

Type of carbohydrate


A diabetic must also remember that the GI score only reflects the type of carbohydrate contained in the food item;  eating a lot of even low-GI foods can also unduly increase the blood sugar level. So one must be conscious about portion sizes to maintain one’s blood glucose level and weight.

It doesn’t also mean that a diabetic should never eat high-GI foods. Here’s where meal planning plays an important role. High-GI foods can be combined with other low-GI foods to balance out the effect on one’s blood glucose levels and have a more nutritious diet.

Diabetic patients usually ask their physicians if alcohol is really bad for them. The answer is yes and no. If one can be disciplined enough to stick to one or two shots of hard drinks, or a glass of wine, it should be fine.

Without wanting to encourage alcohol drinking in diabetic patients,  small amounts of alcohol can actually help control the blood sugar level. Some studies have shown that one alcoholic drink prior to a meal reduces the GI of the meal by approximately 15 percent. However, the usual problem is that many can’t seem to stop after the first alcohol drink. To many, alcohol tastes better after the first drink.

Although alcoholic beverages have been reported to have low GI values, excessive amount can also cause blood sugar levels to drop excessively in those who have had too much to drink and skipped meals because of the drinking spree. Diabetics should also not drink too much beer since it has a moderately higher GI compared to hard drinks. A bottle of beer, max of two, should still be acceptable, though.

Help prevent diabetes

Being GI-conscious could possibly help prevent diabetes in those with a  family history of type 2 diabetes. There are some published researches suggesting that individuals who adhered to a low- to moderate-GI diet developed less diabetes and heart disease on the long term. They also have less postprandial  or after-meal increases in the blood sugar levels—so called glycemic “spikes”—which has been shown in other studies to cause injury to the blood vessels of all body organs.

So blood sugar levels in diabetics and nondiabetics should not only be checked on a fasting state (before breakfast), but also two hours after eating  a regular meal (postprandial blood sugar). A normal fasting blood sugar (FBS) does not mean one has no blood-sugar-related problem. One can also have after-meal elevation of blood sugar or postprandial hyperglycemia—medically called impaired glucose tolerance (IGT)—which may even lead to worse complications. Hence, postprandial hyperglycemia is now considered a major risk factor for atherosclerosis or the narrowing of the blood vessels.

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Most medical organizations concerned with diabetes control support the use of the glycemic index or GI in recommending dietary prescriptions for diabetics and those with tendencies to develop diabetes. So the next time you dine in an eat-all-you-can restaurant, pause a while before you help yourself to another serving, and think GI!

TAGS: column, diabetes, glycemic index, health and science, Rafael Castillo

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