quick overview: the glycemic index

16 May

Since many of the most-recommended eating plans for PCOS patients are based on the idea of glycemic response, I thought it might be a good idea to discuss a couple of things about the glycemic index (and debunk a couple of other myths). Here are a few basic facts about glycemic response, the glycemic index, and how this idea can help you eat better and reduce your PCOS symptoms.

Basics

The glycemic index is a measure of the effects of a certain kind of carbohydrate on blood sugar. Foods with a high GI are the sugars and simple starches that make your blood sugar spike and then plummet (all of those baked goods we love), plus things like potatoes (although these are not as bad as some people have suggested!), and juices or sodas or other sugary drinks. Lower-GI starches include whole grains, beans, some kinds of vegetables, or certain kinds of breads like pumpernickel or rye.

When you hear about “good carbs” vs. “bad carbs,” the difference is the GI. Higher-GI foods set up a number of bad outcomes: the spike in blood sugar causes increased hunger and cravings when it bottoms out, and this eating pattern–over time–can wear out your pancreas, raising your risk of diabetes (especially if you are already insulin resistant, which many PCOS patients are).

In other words, the lower-GI carbohydrates fuel your body without causing drastic ups and downs in your blood sugar–which makes you feel better and is easier on your pancreas. (Eating those lower-GI carbohydrates instead of the sugary or starchy foods can also help you lose weight, especially if insulin resistance is at the root of your difficulties.)

What to Eat
The best books on the glycemic index don’t advocate a radical eating plan. Rather, they mostly suggest reducing carbohydrate portion size and exchanging high-GI carbs for low-GI ones. You can easily find lists of foods by GI on the internet, but it’s really mostly simple (with a few surprises, such as the variation in GI between types of rice). Just choose whole grains, less-processed carbohydrates, and more vegetables instead of starches. (Hey, I said it was simple, not easy.)

The Glycemic Load
You might also hear doctors or nutritionists discussing the glycemic load. This is basically a formula for how much carbohydrate is in a food, multiplied by its GI. The reason it’s useful is that some foods have a high GI, but don’t contain that much carbohydrate, so they don’t affect your blood sugar much. (Carrots are the classic example here.) A food that has a high GI but is low in overall carbohydrate is usually a good choice to eat.

Is this the same as low-carb?
No, it is not. None of these eating plans are low-carb. Atkins, for example, is low-carb, and I do not believe it is a healthful diet at all. But these plans–which have more in common with, say, the South Beach Diet–all emphasize higher-quality foods, better nutrition per calorie, and a balance of macronutrients (that is, a balance between carbohydrate, fat, and protein).

Finally, a Myth
Just because I hear this all the time and read it all the time: no, pasta is not particularly high GI. It’s fine to eat pasta if you can do so wisely and in moderation. It is moderate GI and should be eaten with a low-GI accompaniment. The main reason that so many people struggle with pasta is that Americans tend to eat a lot of it–it should be a moderate serving size, not the only thing you eat at your meal. Also, many people use jarred pasta sauce, which can be a source of a LOT of sugar. Read your label! One sauce that I really like is Victoria marinara (available in most grocery stores, at least on the East Coast, and at Costco). It has no added sugar and it’s delicious.

That said, we eat much less pasta than we used to, because I do find it hard to eat just one serving of it. The main reason I used to cook it was that it was easy: boil noodles, add sauce, and there you have it: dinner! The truth is, though, that it really needs to be just PART of a balanced meal, with more vegetables and possibly a protein source, and at that point I’m cooking anyway and it might be just as easy to cook a whole grain or vegetables instead.

Recommended Reading
My favorite books on this topic are those by Jennie Brand-Miller (she has an assortment; choose the one that reflects your goals or situation!) and the Insulin Resistance Diet. I do also like the South Beach Diet, in many ways, though I find that it is too focused on artificial sweeteners for my taste.

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