Glycemic Index

Glycemic Index is one term I never thought I’d see become popular in the media and weight loss world. Unlike many other junk terms thrown around on commercials, Glycemic Index really can be useful. However, it’s also misused and overused.

Glycemic index (GI) is defined as the increase in blood sugar levels that occur in the body after a certain carbohydrate-rich food is eaten. As a standard, white bread is defined as a GI of 100, and is considered High GI. The lower the GI, the less that particular food spikes your blood sugar.

Why is blood sugar so important? Because the spikes of your blood sugar cause your body to release insulin in order to process (and store) the sugar. These repeated, rapid insulin releases are the primary causes of Type II diabetes or general insulin resistance, and therefore is a major factor in obesity. Blood Sugar is also, contrary to popular opinion, one of the primary factors in heart disease.

Yes, perhaps a much greater factor than dietary fat intake!

Recently several studies on Atkins style diets have shown an overall improvement in many of the markers of heart health. Experts thumb their noses at these studies as: “Everyone knows dietary fat is bad for the heart” (An actual quote I heard on TV from a supposed “Expert” trying to explain away the results of a study he had just completed).

That’s not to say I’m recommending a diet loaded with high fat foods. With the exception of a strict Atkins diet, eating to many high fat foods will make it near impossible to keep your weight under control, and there is certainly an established link between obesity and mortality. As I’ve discussed in a previous article, an Atkins type diet tends to be way too difficult for most people, and many of us don’t react well in terms of how we feel throughout the day without some carbs for energy.

However, the evidence exists that the repeated spikes of insulin due to high GI carb intake is a major factor in the bad health of modern Americans.

So how can we use Glycemic Index, and how is it being misused? In a very broad sense, if we restrict our carbohydrate intake to low GI foods, we are less likely to experience any form of insulin resistance, and therefore reduce the risk of weight gain. High GI foods will also cause us to be hungry again very soon after eating, since they are absorbed so fast. Low GI carbs will also help keep us from eating again as soon since your blood sugar will stay regulated longer.

The problem with the way the diet industry is currently using the Gylcemic Index is that they are defining “Healthy Carbs” by the Glycemic Index. If you’ve read many of my articles, you probably know that I have a problem with the overuse of the word “Healthy.” Healthy for whom, and for what reason? Just because an over processed, nutrient depleted food has a low GI, doesn’t make it healthy. Also, what is “Low GI”, and whose definition of low are we using? I’ve looked at some of these Low GI meals and wonder exactly how the manufacturers are coming up with their definition.

Another misuse of Glycemic Index is that it’s really not the GI of the individual food that counts; it’s the GI of the entire meal that really matters. If all you’re worried about is the blood sugar spike, putting a little oil on your white bread will reduce the GI to a very low level. But is it really healthy? The white bread still contains nothing of nutritional value. It’s still just empty calories, and lots of them.

Where GI becomes really useful is when comparing individual foods for their ability to fill you up and not spike your blood sugar. In other words an Apple (GI of 38) is a better snack than a banana (GI of 56) or rice cakes (GI of 88). Lima beans (32) are better than mashed potatoes (70). You could check this by using a blood sugar meter like a diabetic uses. You’d take readings every 15 minutes after eating the food, but that’s an experiment best left to the experts (yes, I’ve done it). The difference becomes pretty obvious if you’ve ever noticed how an apple will keep the hunger away for quite a while, and after a banana you’ll be hungry again in half an hour.

But GI is not really that useful on a day to day basis. It’s really understanding the theory that helps tell us to ovoid sugary foods, white bread, white rice, or white potatoes. However, we could have also found the same information by looking at the fiber content of each food. In most cases it’s the fiber that makes a carbohydrate low GI, and fiber is also one of the factors I would use to classify a food as “healthy”.

Take bread, for example: You can pretty much tell whether a bread is healthy by its fiber content. Although someone could certainly put fiber back into plain white bread, no one does. In fact, the opposite is true, most “wheat bread” is simply dyed white bread, and is no healthier than plain white bread. It may be fortified, but really does not contain any of the natural fibers or nutrients that were in the grain before it was processed. If you are looking for a “healthy” bread, you are much better off looking for a “whole grain” bread, and then checking the fiber content. I look for at least 4 grams of fiber per slice.

So, yes, GI is a useful concept, but only if you are talking about individual foods in their natural form. Old fashioned oatmeal may have a GI of 48, but Cheerios (despite the manufacturers health claims) has a GI of 78 (processed in your body almost like sugar). Pizza Hut Supreme Pizza has a GI of 33 (because of all the fat that slows digestion), but that doesn’t mean it’s good for your weight loss plan!