Everything You Need to Know about the Glycemic Index

By Steve Edwards

Those of you who pay attention to your diet probably hear a lot about something called the glycemic index (GI) these days. It's become another in a growing list of misunderstood buzzwords in the nutrition world. Today, we'll take a look at everything you need to know about the GI, which is going to take a lot less of your time than reading through the entire GI diet book.

That's not to ding these books, by the way. If you're bored you'll probably learn something by reading any one of them. But in my experience, the glycemic index is not the be-all and end-all of your diet concerns. So I take the opposite approach and say that if you learn to eat properly, you can strike the phrase from your vocabulary entirely.

Simply put, the glycemic index is a way to measure how carbohydrates react in your blood. It's measured on a scale from 1 to 100+, where products with a GI of 55 or under are classified as low GI, those with a GI between 56 and 69 are classified as medium GI, and those with GI of 70 and above are classified as high GI. A high GI number means that a food is quickly converted to glucose in the blood (in layman's terms, a "sugar rush"). The lower the number, the slower the food is converted to glucose. The scale was invented for people with diabetes, but the advent of processed foods becoming a cornerstone of the American diet and the rise of type 2 diabetes have given the average person a good reason to pay attention to the GI index of foods.

Essentially, if we ate nothing but natural whole foods, the GI scale would have little meaning for anyone who didn't have diabetes. Even then, the highest GI foods have low numbers in their natural state. It's the cooking and processing of food that alters it so it breaks down much more rapidly. Eating too much food that is converted to glucose rapidly can lead to type 2 diabetes over time. Pretty much the highest of high GI foods are processed junk foods. There are a few exceptions, which we'll get to, but essentially if we eat a balanced healthy diet with very little junk food, the GI index is far less important to us.

Sugar is the big villain in the GI world. In nature, sugar comes from plants, where it's surrounded by fiber. Fiber in foods slows digestion, lowering the GI number of even foods that are high in sugar, like bananas. Processing, as well as some types of cooking, break down or strip these plants of their fiber. This makes them sweeter to the taste, but it also makes them less healthy. And along with the fiber, processing usually removes a lot of the vitamins and minerals.

The main problem in the American, as stated above, is that we're eating too many processed foods. Although we seem to understand that desserts are mainly sugar, crafty advertisers have been pulling the wool over our eyes by hiding the fact that most American processed foods are not much better for us than sugary desserts are. Breads, cereals, some potatoes and pastas, some rice, crackers, chips, fruit juices, sodas, and condiments, plus almost anything that's ever received a "no fat" label or comes in a box or bag, is high in sugar and probably low in fiber and nutrients. When these processed, packaged foods are all you're eating, you cause your body's insulin response to work overtime. Do this enough, especially without exercise (the great equalizer in the sugar game), and you can wind up with type 2 diabetes.

Of course not every food in the categories I listed above is bad. There are companies that make healthy versions of pretty much everything. But marketers can be tricky. As a consumer, it can be hard to know what you're getting. Even reading food labels can be misleading, which is why every diet that comes with a Beachbody^® program consists mainly of whole, natural foods.

So the very simple rule is to make sure your diet consists mainly of whole, natural foods and you will no longer have to pay attention to the GI index. There are some variables worth mentioning, especially since eating nothing but natural foods can be challenging in today's hectic world. Here are ten quick tips to help you understand the GI index:

1. Desserts. These tend to be mainly sugar and/or fat, and as such, they generally don't try to fool anyone with health claims. If we could keep our desserts small and make them a once-a-day indulgence, we'd have no problems. My tip is to do just that: with desserts, keep a close eye on portion size and frequency. Also, fatty desserts lower the GI influence of the sugar, meaning that, especially if you're insulin sensitive, a richer, fattier dessert might actually be preferable to a "no fat" dessert that's all sugar. But either way, unless you're diabetic or borderline, if indulging in desserts is the only way you stray from your diet, it's not going to cause much harm in the big picture.
2. Sports. When you're active, and especially when you're operating at your physical limit, your body burns up its stored carbohydrates (known as blood sugar) very rapidly. During and after hard or long bouts of exercise, sugar isn't bad for you—in fact, it's actually good for you. This is the only time this is true. Unfortunately, we often like to eat sugary stuff at the opposite times, like when we're watching TV, and no Wii Fit^® game has yet been designed that'll burn off blood sugar unless you do it all day long. When you're not active, you should severely limit your sugar intake.
3. Sports drinks are for sports. This may seem redundant, but Gator/Power/Acceler-ades et al are only good when you're playing sports that make you sweat. This is also true for things like P90X^® Results and Recovery Formula^®. These are not your standard foods. They're formulated for when you're playing sports vigorously. The difference between the "-ades" and Results and Recovery Formula is that the former only give you sugar and a small amount of electrolytes you lose when you sweat, whereas the latter uses its sugar (which gets absorbed rapidly when you're out of blood sugar) to transport all sorts of other nutrients to help repair your body after exercise. Oh, and also that the "-ades" market themselves as things you might want to drink all day long, exercising or not.
4. Salads are your friend. Not only are they loaded with fiber, but many of the things we tend to put on salads, including vinegar, lemon juice, and lime juice, as well as pickled vegetables, etc., tend to have acids that lower the GI index of other foods.
5. Add protein to all your meals. Like fats, proteins slow absorption rates of high GI foods.
6. Use semolina or whole wheat pastas. These have a much lower GI number (around 30 to 55) than pasta made from refined, enriched white flour.
7. Use long-grain or brown rice. All rice is fairly high in the GI index, but long-grain rice can be fairly low (50 to 60), whereas white short-grain rice can be as high as 130.
8. Eat crisp fruit. Fruit is not a real concern unless your diet has an inordinate amount of it. If so, the mushier—and sweeter—a fruit becomes, the higher its GI number. But even the sweetest fruits, like ripe papaya, are only around 60.
9. Beware of fluff. Fluffy and puffy foods tend to have a high GI number. Cereals are a good example. When a cereal is chewy, that generally means it has more fiber and is less processed, as opposed to soft, fluffy cereals that have been excessively processed and injected with air (and sugar). Potatoes, especially white, fluffy ones, can have extremely high GI numbers, often in the 90s. Fortunately, we tend not to eat potatoes plain, and, as stated above, adding meats, fats, and acidic ingredients will bring the number way down. Oddly enough, sweet potatoes, despite the deceptive name, have a very low GI number. Yams, too.
10. Some sugar can be OK. If you see a trend here, it's that sugar speeds itself into your system, and if this is your primary mode of eating, it's bad. However, sugars can also speed other nutrients into your system, so you'll sometimes see sugar as an ingredient alongside a lot of healthy nutrients to serve this purpose. A good example is Beachbody's Shakeology^® meal replacement shake. It has around 10 grams of sugar (40 calories) in a serving that also contains a lot of protein and 70 other healthy ingredients. In lab tests, Shakeology scored a 24* on the glycemic index, as low as a lot of vegetables. So while sugar is generally the GI villain, you need to look at the entire profile of the foods you're eating before you pass judgment.

*Shakeology was tested by Glycemic Index Laboratories, Inc., a premier facility for testing the metabolic responses to foods and ingredients. GI Labs is the only lab in North America recommended by the Glycemic Index Foundation. GI Labs follows a Determination Standard protocol of testing in vivo with ten human subjects. GI Labs' protocol exceeds the standards set by the World Health Organization.