What is the Glycemic Index and Glycemic Load?

Glycemic this and glycemic that. Does it even matter?

I’m asked this question often enough by my clients. When you do your own research about what to eat, when, and why, you’ll find a confusing mess of information out there. Here’s how to make things clearer with respect to glycemic load and index.

First, you'll notice that they both begin with "glycemic." That's one tip that they have to do with sugars and carbs. Not only how much sugar is in foods, but more importantly, how it affects your blood sugar levels.

In general, diets that are high on the glycemic index (GI) and high in glycemic load (GL), tend to increase the risk of diabetes and heart disease.

Fact: Starches like those in potatoes and grains are digested into sugar; this is because a starch molecule is a chain of sugars linked together. Digestive enzymes break those bonds so that the sugars become free and can be absorbed by your body. When those sugars are free, they affect your body the same way that eating sugary foods does.

Glycemic Index (“how fast”)

The most common of the two terms is “glycemic index” (GI).

As the name suggests, it "indexes" (or compares) the effect that different foods have on your blood sugar level. Then each food is given a score from 0 (no effect on blood sugar) to 100 (big effect on blood sugar). Foods that cause a fast increase in blood sugar have a high GI. That is because the sugar in them is quickly processed by your digestive system and absorbed into your blood. They cause a “spike” in your blood sugar.

So, you can probably guess that pure glucose is given a GI rating of 100. On the other hand, chickpeas are right down there at a GI of 10.

Glycemic Index Rating:

  • Low is anything under 55;
  • Moderate is 56-69, and
  • High is 70+

An important distinction to make is that a food’s Glycemic Index rating is a measure of how fast a carbohydrate containing food is digested and raised your blood sugar. It's not a measure of the sugar content of the food.

How the carbohydrates in food affect your blood sugar level depend on other components of the food. Things like fiber and protein can slow the release of sugar into the bloodstream, and this can make even a high-sugar food, low on the GI scale.

So, lower GI foods are better at keeping your blood sugar levels stable because they don't increase your blood sugar level as fast.

Fact: Can you guess which food has a GI of higher than 100? (Think of something super-starchy) White potatoes! They have a GI of 111.

Glycemic Load (“how much”)

The glycemic load is different.

Glycemic load (GL) doesn’t take into account how quickly your blood sugar “spikes”, but it looks at how high that spike is. Basically, how much the food increases your blood sugar.

GL depends on two things. First, how much sugar is actually in the food. Second, how much of the food is typically eaten.

Glycemic Load Rating:

  • Low GL would be 0-10,
  • Moderate GL would be 10-20, and
  • High GL would 20+

Example of GL and GI

So, let’s compare average (120 g) servings of bananas and oranges:

Food GI Serving size (g) GL per serving
Banana, average 48 120 11
Oranges, average 45 120 5

Excerpt from: Harvard Health Publications, Glycemic index and glycemic load for 100+ foods

As you can see, the banana and orange have almost the same glycemic index.; this means they both raise your blood sugar in about the same amount of time.

But, the average banana raises the blood sugar twice as high (11) as the orange does (5). So, it contains more overall sugar than the same amount (120 g) of orange.

Of course, this is all relative. A GL of 11 is not high at all. Please keep eating whole fruits. 🙂

What does this all mean for your health?

Certain people should be aware of the effects that foods have on their blood sugar. People who have diabetes or pre-diabetes conditions like insulin resistance need to be aware of the glycemic index and glycemic load of foods they are eating regularly.

The GI and GL are just two factors to consider when it comes to blood sugar. Some high GI foods are nutrient-rich, but if you want to reduce the impact on your blood sugar, have them with a high-fiber or high-protein food.

Conclusion

If you have blood sugar imbalances or diabetes, you should probably be aware of the GI and GL of your food.

If you are at risk of diabetes or heart disease, you might try swapping out some higher GI/GL foods and replacing with lower GI/GL foods.

It’s a good idea to be aware of the GI and GL of the foods you’re eating to give you a deeper understanding of how your food choices affect your body.

Oh, and try this low GI recipe I have for you.

Recipe (low GI): Mediterranean Salad

Serves 2

1 cucumber, chopped
½ cup chickpeas, drained and rinsed
½ cup black olives
¼ red onion, diced
½ cup cherry tomatoes, halved
¼ cup extra virgin olive oil
1 Tbsp. apple cider vinegar
2 Tbsp. lemon juice
1 tsp garlic
1 tsp basil
½ tsp oregano
1 dash sea salt
1 dash black pepper

Place first five ingredients together in a bowl.

Add remaining ingredients to a jar (to make the dressing) with a tight-fitting lid and shake vigorously.

Add dressing to salad and toss to coat.

Serve & enjoy!

Tip: Add chopped avocado for even more fiber and healthy fat (both blood sugar balancing benefits).

References:

http://www.health.harvard.edu/diseases-and-conditions/glycemic_index_and_glycemic_load_for_100_foods

http://lpi.oregonstate.edu/mic/food-beverages/glycemic-index-glycemic-load

Selina Rose
A holistic nutritionist, writer, non-granola yogi, and coach dedicated to helping you find sustainability in your health so you can play full-out in life (whatever that looks like for you).
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Author: Selina Rose

A holistic nutritionist, writer, non-granola yogi, and coach dedicated to helping you find sustainability in your health so you can play full-out in life (whatever that looks like for you).