Just like many health and fitness fads, the Glycemic Index has been hijacked by food marketers and manipulated to sell more products. Walk down the processed junk aisle of any supermarket, and you will see lots of packaging with the term “Low Glycemic” on it. The consumer has been conditioned to equate “low glycemic” with “healthy carbs.” However, is this truly the case?
What is it?
In concept, the Glycemic Index is a good one. First published in 1981, the concept is to categorize foods based on how they affect your blood sugar. Foods that fall into the “low glycemic” range in theory should have a minimal impact on your blood sugar – meaning your blood sugar doesn’t spike when you eat them. Carbohydrates that are “low glycemic” include mostly nutrient-dense foods that are usually higher in fiber.
“High glycemic” foods on the other hand have a significant impact on your blood sugar by elevating the glucose in your bloodstream. These “high glycemic” carbohydrates are generally highly processed foods with high levels of sugar, and low fiber content. When consuming these carbohydrates, there is an immediate response in increased levels of glucose (the sugar in your blood).
High levels of glucose in your blood for a prolonged period of time can lead to many health problems such as, but not limited to, Type-II Diabetes, Liver and Pancreatic disease, and Obesity. For the health conscious person, monitoring and controlling the glucose response from the food you eat could be an important metric to know how to measure. Unfortunately, without wearing a continuous glucose monitoring device like the Dexcom it is very difficult to know how the foods you eat are affecting your levels of glucose.
The Glycemic Index enters the room
Without wearing a glucose monitoring device like the Dexcom, accurately knowing the glucose response you have to certain foods is nearly impossible – the Glycemic Index was created to do just that. Unfortunately, it comes with many flaws that if not carefully monitored, can significantly change your results.
The Flaws
To find the flaws, let’s first look at the unit of measurement that is used to determine where the food falls on the Glycemic Index. Scientists use 50 grams of digestible carbohydrates per food item to determine how much it raises your blood sugar. In science and research, it is important to have a baseline unit of measure to be able to accurately compare and contrast. Using 50 grams of digestible carbohydrates as the serving size creates an even playing field for measuring your glucose response.
This is where the first major flaw of the Glycemic Index reveals itself. Although it is necessary for the accuracy of comparison, to measure all foods using the same amount of digestible carbohydrates (50 grams) creates some misleading results if you’re ignorant of the portion size that is being measured.
Let’s take a look at a high quality, nutrient dense whole food that a lot of people enjoy during the summer months, watermelon. In the 15+ years that I have been helping people better their health, I have never come across someone who developed diabetes or obesity because they over-consumed watermelon. However, with a Glycemic Index score of 72, watermelon is considered a High Glycemic carbohydrate. But before you go ditch the watermelon this summer, you need to consider the serving size used to measure the results.
In order to get 50 grams of digestible carbohydrates of watermelon, you would need to consume five cups of diced watermelon… FIVE CUPS. The normal serving size of watermelon is about two cups, which would significantly change the results that it has on your blood sugar.
Ice cream, another popular summer snack, has a Glycemic Index score of 62 which puts it into the category of “Medium Glycemic.” However, to reach the required 50 grams of digestible carbohydrates of ice cream, it only requires one cup of ice cream. Starting to see the major flaw?
I think that everyone can agree that ONE cup of watermelon is definitely healthier than ONE cup of ice cream. However, when you compare FIVE cups of watermelon, to ONE cup of ice cream, the results will tell you that the watermelon will have a higher impact on your blood sugar.
How food is measured isn’t the only flaw in the Glycemic Index. Another major flaw is the relationship that food has with each other. To accurately measure the Glycemic Index number of each different food, the food itself must be consumed alone. Protein, fat, and fiber can all play a role in lowering the impact that a food has on your blood sugar. The fat found in ice cream VS the absence of fat in the watermelon could be another factor of why ice cream falls lower on the Glycemic Index as watermelon.
Generally speaking, the majority of us consume more than one type of food with our meals. By combining food groups like we do with our meals, the Glycemic Index becomes significantly more inaccurate. Unless you are eating JUST a bowl of rice with nothing else, you can’t accurately determine the impact of the rice itself.
If this is not enough evidence to show you the flaws of the Glycemic Index, here are a couple of more things to consider. The Glycemic Index of food can change on a broad spectrum for each individual. In a study conducted amongst 800 people, the glycemic response to consuming a piece of white bread had a huge range of responses. Some people had as much as a 5 times the spike of glucose compared to other people.
Not only does the Glycemic Index of food vary when comparing individuals, it can also vary significantly within each individual. Based on factors such as how much sleep you got the night before, your physical activity, what foods were consumed the day before, and alcohol consumption, the Glycemic Index scores can have a variance of 17% – 31%.
As you can see there are many factors that, once exposed, show the true nature of the Glycemic Index. Does this mean that you should completely ditch using the Glycemic Index to determine if what you’re eating is good for you? Of course not! Just like you wouldn’t judge a book by its cover, you shouldn’t judge a food by its Glycemic Index.
The Glycemic Index gives you a quick and easy way to determine the impact that a food might have on your blood sugar. However, it should be used just as another tool to learn about your personal relationship with food. It is just one of many factors that goes into choosing the right foods for you, and doing what’s best for your health.
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