Worrying About the Little Things With the Glycemic Index

By: Gavin Hemmerlein

Prepare yourself. This is going to get “quotey” up in here.

So in my CHO post I mentioned how the Glycemic (GI) is not really that big of a deal. I think it went something like this:

“So I’m expecting most of you have now Googled the GI to find out what to avoid. Here’s the beauty of it all… The GI was done on fasted individuals with solely a carbohydrate meal. Read that again slowly. This is part of the reasons behind one of my dietary recommendations. For a mixed meal (proteins and fats included in the meal), the GI is affected GREATLY. It is to the point that it is nearly pointless to follow. It can also be modified with a high intake of fiber because fiber is nearly impossible to digest (hence why it does a great job of “cleaning you out”). So always have your protein spread out evenly throughout your meals (for even more reasons that I will get into on my Muscle Protein Synthesis post). This will attenuate your GI “spikes” and will also help you feel satiated (protein is far more satiating than CHOs).”

This is an incredibly confusing subject that most people get wrapped around unnecessarily. I do want to say that if you have issues with insulin (diabetics especially), do not follow the advice that I am about to tell you. Your situation is unique. Most likely a lot of the following advice will apply to your diet structure, but that’s not for me to advise; discuss with your general practitioner.

Let’s first realize that the GI was studied for diabetics. This is an effort to prevent them from, oh I don’t know, not entering a coma. Let’s list some myths that are presented by UNM on the subject:

Myth #1 The Glycemic Index is the best way to determine the amount of carbohydrate (sugar) in a particular food.

[The] Glycemic index describes the rate glucose is released in the bloodstream and says nothing about carbohydrate content. The more grams of carbohydrate consumed the higher the glycemic response because there is an increased glycemic load. For instance, you could eat two different foods with a similar GI but the blood glucose response will be greater for the food eaten in higher concentration.

Myth #2 Avoid foods that are white such as pasta and potatoes because they are high GI foods.

The white color of foods doesn’t necessarily mean it has a high GI. As mentioned previously, cooking method, amount of processing as well as meal composition affect GI, not food color. For example, the GI of boiled potatoes is substantially lower (56) than when microwaved potatoes (82). What many don’t realize is that pasta is a low GI food (40-50). Also, we usually eat foods in combination so the fat and protein consumed at mealtime serve to lower the overall GI of some meals.

Myth #3 The Glycemic Index Can Be Used to Assess How Healthy vs. Unhealthy foods.

The GI doesn’t indicate whether a food is healthy or not. One example of this is milk. Whole milk has a GI of 27 while skim milk has a GI of 32. Lower GI doesn’t always mean a healthier product.

Myth #4 All Simple Sugar is High GI

Not all sugar is created equal. Fruit, for instance, contains the simple sugar fructose. This simple sugar has a slower rate of digestion and absorption than glucose, therefore it produces a lower glycemic response. The GI for most raw fruit is between 30-50.

Myth #5 I Can eat as much Low GI food as I want and maintain low insulin levels

Some feel that low GI eating entitles them to consume as much as they want. It is possible to get high insulin responses with low GI eating. Remember, glycemic response is a combination of GI x carbohydrate concentration (glycemic load), so the more grams of carbohydrate consumed will result in higher insulin levels.” [1]

To add more onto this, it is extremely unlikely that eating according to the GI will prevent you from getting diabetes. [2, 3] So you won’t have to go on a commercial with Wilford Brimley because of the GI. That isn’t to say it doesn’t help WHEN you have diabetes, just that you won’t GET diabetes from a certain GI diet.

As for when you’re eating mixed meals? Well let’s let the writers for a Clinical Diabetes article (Amanda R. Kirpitch, MA, RD, CDE, LDN, and Melinda D. Maryniuk, MEd, RD, CDE, LDN) go over that one:

“Protein/fat: Adding protein or fat, which have minimal effects on glycemic excursions, to a high-GI food will decrease the GI of that food. For example, adding cheese to a slice of bread would decrease the GI.

Soluble fiber: In general, the higher the food is in viscous or soluble fiber, the lower its GI will be. By increasing the viscosity of the intestinal contents, the interaction between the starch and the digestive enzymes is slowed, resulting in slower and lower glycemic excursions. Beans are a great example of a food high in soluble fiber.” [4]

This is yet another reason why I recommend mixed meals. This will keep you from sweating the small stuff and carrying a pocket GI Table with you. There’s more important things in life.

Sources:

  1. Mayo, Jerry J., PhD RD, Kravitz, Len, Ph.D. “Glycemic Index and Weight Loss.” Glycemic Index and Weight Loss. University of New Mexico, n.d. <http://www.unm.edu/~lkravitz/Article%20folder/glycemicUNM.html >
  2. Dietary glycemic index and glycemic load are associated with high-density-lipoprotein cholesterol at baseline but not with increased risk of diabetes in the Whitehall II study. <http://ajcn.nutrition.org/content/86/4/988.abstract >. Am J Clin Nutr October 2007 vol. 86 no. 4 988-994
  3. Geng Zhang, An Pan, Geng Zong, et al. Substituting White Rice with Brown Rice for 16 Weeks Does Not Substantially Affect Metabolic Risk Factors in Middle-Aged Chinese Men and Women with Diabetes or a High Risk for Diabetes. Annhild Mosdøl, Daniel R Witte, Gary Frost, et al. <http://jn.nutrition.org/content/141/9/1685.abstract >. First published July 27, 2011, doi: 10.3945/jn.111.142224
  4. Kirpitch, Amanda R., MA, RD, CDE, LDN, and Melinda D. Maryniuk, MEd, RD, CDE, LDN. “Clinical Diabetes.” The 3 R’s of Glycemic Index: Recommendations, Research, and the Real World. Clinical Diabetes, 2014. Web. 19 Sept. 2014. <http://clinical.diabetesjournals.org/content/29/4/155.full >
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