What are the glycemic index and load?

Glycemic: what does it even mean?

I’m sure you’ve heard the terms “glycemic index” and “glycemic load” used in discussing the merits of including certain foods in your diet. I admit that it was Greek to me for many years! What’s all of this “glycemic” talk about, however, and does it really matter?

Glycemia refers to the presence of glucose in the blood. Hypoglycemia is a medical condition that occurs when your main source of energy–blood sugar–drops very low. Glycemic index (GI) and glycemic load (GL) are tools used to measure the rate and intensity with which the food you take in causes your blood glucose level to increase. They are a means to assess the effects of sugars and carbs on our health.

GI refers to how quickly a carbohydrate-containing food is digested and raises your blood sugar. GL focuses on how high the carb-heavy food spikes your blood sugar; in other words, how much the food increases your blood sugar.

In general, if your diet consists mostly of foods that are high on the glycemic index (GI) and high in glycemic load (GL), you run a greater risk of developing chronic illnesses, such as diabetes and heart disease.

Glycemic index (“how quickly”)

The most common of the two terms is glycemic index (GI). As the name suggests, it indexes or compares the effect of a variety of foods on your blood sugar level. Then, each food is given a score from 0 (no effect on blood sugar) to 100 (tremendous effect on blood sugar). Foods that cause a speedy increase in blood sugar have a high GI. The sugar in those foods is quickly processed by your digestive system and absorbed into your blood. It then causes a spike in your blood sugar.

So, you can probably guess that pure glucose is given a GI rating of 100, as is a slice of white bread (go figure!). On the other hand, chickpeas are close to the bottom with a GI of 10.

When a food item is rated on the GI, low is anything under 55; moderate is 56-69, and 70+ is considered high.

Once again, glycemic index measures how fast a carbohydrate-containing food is digested and raises your blood sugar. It is not a measure of the sugar content of the food.

How the carbohydrates in food affect your blood sugar level depends on other components of the food. For example, fiber and protein can slow the release of sugar into the bloodstream and, thus, make even a high-sugar food low on the glycemic index. So, foods that are at the lower end of the GI are better at keeping your blood sugar levels stable because they don’t increase your blood sugar level as quickly.

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

Glycemic load (“how much”)

Glycemic load (GL) doesn’t take into account how quickly your blood sugar spikes, but it does look at how high that spike is. In other words, the focus is on how much the food increases your blood sugar.

GL depends on two things:

1. How much sugar is actually in the food.
2. How much of the food is typically eaten.

A food item’s GL is determined by multiplying its glycemic index by the number of carbohydrate grams in a serving. You then divide that figure by 100. A low-glycemic-load reading would fall between 0 and 10,  a moderate GL level would be between 11 and 19, and a high GL would be 20 or higher. Anyone diagnosed with diabetes should aim for GL in the low (0-10) range.

Examples of glycemic index and glycemic load

 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 rating, which means that they both raise your blood sugar in about the same amount of time. However, the average banana raises blood sugar twice as high (11) as the orange does (5), so it contains more overall sugar than the orange, even though both are the same serving size of 120 grams.

Of course, these figures are all relative. A GL of 11 is not high at all, so don’t let the banana’s glycemic load keep you from eating it. Keep on consuming whole fruits!

What does this all mean for your health?

People dealing with diabetes, pre-diabetes, and insulin resistance need to be aware of the glycemic index and glycemic load of foods they are eating regularly and their effects on their blood sugar.

For example, starches found in potatoes and grains are digested into sugar because starch really consists of a bunch of sugars linked together. Digestive enzymes break those bonds so that the sugars become free. Then those sugars affect your body the same way that eating sugary foods do.

However, GI and GL are just two factors to consider when it comes to blood sugar. Some high-GI foods are pretty good for you, but if you want to reduce the impact on your blood sugar, make sure to eat them with a high-fiber or high-protein food.

To sum up…

If you have blood sugar imbalances or diabetes, you should be aware of the GI and GL of your food. And if you are at risk for diabetes or heart disease, you might try swapping out some higher GI/GL foods for lower GI/GL foods.

Recipe (low-glycemic index): Mediterranean Salad

Serves 2

Ingredients:

• 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

Directions:

1. Place first five ingredients together in a bowl.
2. Add remaining ingredients to a jar (to make the dressing) with a tight-fitting lid and shake vigorously.
3. Add dressing to salad and gently toss.
4. Serve and enjoy!

Tip: Add chopped avocado for even more fiber and healthy fat.

Which of your favorite foods are high on the glycemic index or carry a high glycemic load?