The Glycemic Index Explained

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Filed Under: Blood Sugar, General Health
Last Reviewed 02/06/2014

The Glycemic Index Explained

Understand how food raises your blood sugar levels

As science delves deeper into the diet vs. weight relationship, research is showing that not all carbohydrates are the same. The differences between carbohydrate foods can be described in relation to their glycemic index.

Simply put, this index, which goes from 100 to 0, indicates how quickly a food raises blood sugar levels. Glucose is rated at 100, and the closer to 100 a food is rated, the more it affects blood sugar levels.

Those foods with a low glycemic index (55 or less), such as most vegetables, don’t elicit as much of an insulin response and don’t lead to the deposition of fat the way those with a high index (70 or higher) do—foods such as white bread, potatoes, and pasta.

This notion was shown to be the case again in a study of 572 adults. Researchers at the University of Massachusetts Medical School collected reports from these individuals concerning their food consumption and physical activity from 1994 to 1998. Once again, it was determined that the daily carbohydrate intake and total calories from carbohydrates aren’t the prime determinant when it comes to weight gain or loss. The determining factor is the type of carbohydrates. High-glycemic carbohydrates were shown to increase insulin production and increase fat storage.

The fad of cutting out all carbohydrates from the diet in favor of an all-protein-and-fat diet isn’t a good idea, nor is it a diet that can be safely or easily sustained for the long term. The truth of the matter is that you need to eat the right proteins, the right carbohydrates, and the right fats. It’s both the type and quality of these components that matter more than the quantity.

Most people on the Atkins diet or those like it don’t realize what’s driving their weight loss. Studies have shown that once they begin to eat more nutrient-dense proteins and fats, they felt more satisfied. When the carbohydrates are removed from the diet (or restricted to, say, 20 grams a day in the diet), they spontaneously reduced their energy consumption by 1,000 calories. Even though the amount of protein and fat they are allowed to consume is basically unlimited, they didn’t compensate for the loss of calories by eating more of those type foods. Not only do simple carbohydrates stimulate the appetite, they are not “nutrient-dense” enough to create a feeling of fullness and satisfaction.

In a nutshell, to lose weight and, more importantly, to be able to maintain the proper weight without constant dieting and/or starving, one has to eliminate sweets and sweeteners (which have been shown to interfere with the body’s ability to feel satisfied). And counting calories is no longer necessary once you begin to listen to your body and feed it the complex low-glycemic carbohydrates, high-quality protein, and natural, non-processed, non-rancid fats that it craves.

Eat Low-Glycemic Foods

In general, figuring out where foods fall on the glycemic index is intuitive. Most sugars and items made from white flour have a high glycemic index, while the majority of vegetables and fruits have a low glycemic index. There are a few surprises, however. For instance, ripe bananas, raisins, and rice cakes all have high glycemic values.

There are many charts and lists of high-, medium-, and low-glycemic foods online and in books, like The Complete Guide to Fat-Storing Carbohydrates, which lists 1,000 foods by glycemic rating. It’s available from the Glycemic Research Institute, at 727-894-0042. 

Cut Out White Sugar

Sugar has a high glycemic index value. Consuming sugar is the fastest way to drive up your blood sugar levels, and out-of-control blood sugar will play havoc on your health. Getting sugar out of your diet can significantly reduce your risk of serious disease.

You’ll have to read labels carefully, though, because sugar is often hidden in unexpected ingredients such as sucrose, dextrose, lactose, high fructose corn syrup, malt syrups, maple syrup, and fruit juice concentrates.

Instead of consuming these unhealthy sugars, you can satisfy your sweet tooth with xylitol. It’s a natural sweetener made from a compound found in certain vegetables, strawberries, raspberries, plums, and jute, as well as from some hardwood trees such as birch. It’s equal in appearance and exchange to sugar, but it has some remarkable health-promoting abilities, too. Xylitol has been shown to help prevent sinus infections, bronchitis, pneumonia, and middle ear infections. It’s also a powerful tool for fighting dental cavities and plaque formation.

Another sugar substitute that I recommend is stevia, which is a natural sweetener extracted from a shrub in the sunflower family that’s found primarily in South America. It has a subtle herbal flavor, and comes in a very concentrated powder form. Sweetness varies by the brand, depending if fillers are used, and modern production methods don’t create an aftertaste as older methods did. You can find stevia in most natural food stores.

A final sugar substitute I want to mention is blackstrap molasses. It comes from sugar cane but, unlike white sugar, it’s full of healthy minerals, including iron, calcium, and manganese. Look for the unsulfured kind.

Eliminate White Flour, Too

Like white sugar, white flour has a high glycemic value and can cause blood sugar control problems. There are several healthy, tasty, and readily available alternatives you can try.

Oat flour tastes a lot like white flour, but is much healthier. It’s lower on the glycemic index and is a rich source of soluble fiber, which has a stabilizing effect on blood sugar, as well as the nutrient beta glucan, which boosts the immune system. Beta glucan is also a special kind of antioxidant that has anti-inflammatory properties. I recommend grinding your own oat flour: Simply buy organic rolled oats and grind them as fine as you need in a typical electric coffee grinder. Grind only what you require for the recipe at hand, for maximum freshness.

Whole wheat flour includes the bran and germ of the wheat kernel, which are abundant in vitamins, minerals, protein, fiber, and antioxidants. For a lighter version of 100 percent whole-grain wheat flour, try King Arthur White Whole Wheat Flour. It’s made from a white wheat berry rather than the traditional red wheat.

Rye flour has a stronger flavor than wheat flour, but is higher in fiber, has a lower-glycemic value, and has less gluten.

These simple substitutions will go a long way to trimming your waist as well as improving your overall health. Remember: not all carbs are created equal, and the glycemic index is a great tool to evaluate the healthfulness of the your diet to help you achieve and maintain your ideal weight.

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