Posted by: Hil | October 24, 2008

Glycemic Index, Part I

I know that I throw around the terms glycemic index and glycemic load as though everyone is familiar with them.  They are so central to the way that I eat that it is hard not to!  But every now and then I stop myself and remember that many people have no clue what I am talking about.  And I just realized that I’ve never given a very thorough explanation of the glycemic index on the blog.  I’ve mentioned it briefly in my FAQ and in my post about the South Beach Diet, but I’ve never really given a decent explanation of what I’m talking about.  So I’m going to give it a shot.  If nutrition talk is boring to you, stop now…I promise there will be more pictures of food soon!  Bear in mind that I am not a scientist, a doctor or a nutritionist.  I am going based on my best understanding of what I have read.  While I have done a lot of reading about the glycemic index, my primary sources for this information are Walter Willett’s books, Andrew Weil’s Eating Well for Optimum Health, and

The glycemic index is a way of measuring the effects that various carbohydrate sources have on the body.  The glycemic index (GI) is a scale from 1-100 that measures how much carbohydrates from various foods raise a person’s blood sugar when eaten on an empty stomach.  Foods high on the glycemic index cause a rapid spike in blood sugar, while foods lower on the glycemic index cause a more moderate blood sugar response.  Glycemic load (GL) takes the numbers from the glycemic index and adjusts them for the quantity of carbohydrate in a normal serving of a given food.  To illustrate, carrots and potatoes are both high on the glycemic index.  However, because carrots are relatively low in carbohydrates, their glycemic load is low.  While this is a very broad generalization, whole foods tend to be lower on the glycemic index while highly processed carbohydrates are at the very top. 

Why does it matter?  In the short term, eating low GI foods will keep your blood glucose levels more even and may help you to stay full longer after meals.  Low-GI diets help some people to lose weight in this manner.  (It definitely helped me!)  In the long term, a low GI diet reduces your risk of developing various diseases.  Data from the Nurse’s Health Study suggests that a high GI diet is correlated with increased risk of type II diabetes and coronary heart disease.  In contrast, the percentage of calories from carbohydrates and fat was not correlated with increased risk of these diseases.  Bottom line:  when it comes to decreasing your risk of long term disease, the quality of the carbohydrates you consume matters much more than the quantity.

Stay tuned for Part II, in which I will explain some simple ways to lower the glycemic load of your diet.



  1. I’ve always been a little unclear about the glycemic index, and what it all means. Thank you so much for this post!! I’m definitely looking forward to reading Part II.

  2. Thanks, since I am hypoglycemic, this info is very interesting to me. I keep saying that I need to read more so that I can help myelf so thanks for the post, I look forward to part II!

  3. Thanks 🙂 I never really knew the details before. Sounds like it makes sense though!

  4. This is a great explanation. I actually just had an exam on the GI and the effects in the body this morning, and you nailed it:) I like this post too because it helps people understand that carbs aren’t the enemy, it is, as you said about the QUALITY of the carbs not the QUANTITY. Well said!

  5. […] Index, Part II –Tips on Lowering the Glycemic Load of Your Diet In Part I, I did my best to explain the basic ideas behind the glycemic index and why I consider it so […]

  6. wow,i’m glad to find this post,you’ve listed lots of informational advices here.thanx alot

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