What is the Glycemic Index?
Who knew eating would turn into a science fair? It seems like it nowadays, doesn’t it? We have indices, different types of carbs, macronutrients, scales, calculators and headaches.
Still— you’re here—to feed your mind with some knowledge. Getting buff on some blogs is a good sign that you are a health warrior.
So, let’s scarf down some knowledge on the glycemic index.
Whether you first heard this term from your trainer, friend or nutritionist, or you heard it because you have medical issues with blood sugar, it’s important to understand it so you can make smart choices on food.
The glycemic index is a number that indicates how quickly your body will convert the carbs of that good into glucose (sugar).
The smaller the number, the less impact the food has on your blood sugar.
- 55 or less = Low (good)
- 56 to 69 = Medium
- 70 or higher = High (bad) (kind of—see below regarding Glycemic Load)
Typically, the more natural the food is to how they’re found in the ground, vine or in a tree, the lower the glycemic index.
In other words, whole plant foods will typically be lower than processed/refined foods with added sugars.
But when it’s all said and done, what does it mean exactly—the impact of food on your blood sugar?
Food and Glycemic Value
The higher the foods’ glycemic index, the more quickly your blood sugar levels will raise. This is because of the way your body processes those types of carbs. They are usually simple carbs with one or two molecules of sugar that the body converts quickly into glucose to use for energy.
The lower the number, the more slowly the body digests the carb. This usually indicates it is a complex carbohydrate. Complex carbs like many vegetables and starches are not digestible, in terms of their sugar molecules. They pass through the stomach and are absorbed in the intestines. They are important for intestinal health and, of course, energy.
A lot of people think carb counting is all you need. But that’s not the case. As you can see, the two forms of carbs impact blood sugar very differently, and as such, impact health very differently. Therefore, if you have a medical condition like diabetes, or you are carb-counting you can use the glycemic index to identify good carbs from bad carbs.
Your targeted GI for your meal will also depend on your level of activity and health. For instance if you are going to partake in an endurance event, you’ll likely seek high GI foods to provide quick energy. If you’re watching your blood sugar, you’ll want to stick to the lower GI foods.
But, just because you know the number, doesn’t mean it stays the same—the longer you cook starches increases the GI value, the more ripe some foods are like bananas can increase its glycemic value and adding acids like vinegar during cooking can lower the glycemic index.
Additionally, you need to do some final math before you make your final food selections.
Glycemic Load of Food
Another factor is knowing how much glucose that food delivers. It’s not just about how quickly your body will convert the food to sugar, but how much sugar it will load into your bloodstream.
This value is aptly named glycemic load.
You can determine the amount of glucose a food will load into your blood by taking the number of the grams of carbs in one serving, multiplying it by the GI number and then dividing it by 100.
Carbs (g) x GI / 100
A glycemic load of:
- 10 or below is considered low
- 20 or above is considered high
This is really important to understand because you may make incorrect assumptions about foods based solely on their GI value.
According to Diabetes.org “Watermelon, for example, has a high glycemic index (80). But a serving of watermelon has so little carbohydrate (6 grams) that its glycemic load is only 5.”
So you can definitely start with low to medium GI, but if a natural food has a higher GI, do a little more math before you scratch it off your list. Watermelon, in particular, is chock-full of citrulline which is actually great for cardiovascular health.
So, there you have it–you probably know more than most now about glycemic index.
Your brain just got bigger–and it looks good. Real good.