You need to understand the glycemic index and glycemic load and how it impacts our body.
Glycemic = sugar found in carbohydrates. Not only how much sugar is in food, but more importantly, how it affects your blood sugar levels.
In general, diets that are high on the glycemic index (GI) or high in glycemic load (GL), tend to increase the risk of insulin resistance, pre-diabetes, type two diabetes and heart disease. Don't think you're at risk?
In 2010, over 2.5 million Canadians were diagnosed with insulin resistance (precursor to type 2 diabetes). In the US, the National Institute of Diabetes and Digestive and Kidneys Diseases reports that 84 million (that's 1 in 3 adults) have insulin resistance.
The glycemic index and glycemic load matter.
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. The sugar content is quickly processed by your digestive system and absorbed into your blood, and the food (and its sugar content) causes a “spike” in your blood sugar.
With this math in mind, science has given pure glucose (pure, white refined sugar) a GI rating of 100. On the other hand, chickpeas are at the bottom of the scale with a GI of 10. Regarding GI: low is anything under 55; moderate is 56-69, and 70+ is considered a high GI food.
Remember, this is a measure of how fast a carbohydrate-containing food is digested and raises 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.
Fat, fiber and protein can slow the release of sugar into the bloodstream, and this can make a high-sugar food, low on the GI scale. For example, cheerios have a higher GI than M&M peanuts. Cheerios enter the bloodsteam faster than M&Ms because the fat and protein in the peanuts slow the rate at which the chocolate and candy sugar enters the bloodstream. Crazy, but true. This is why many "bars" include a combination of fat, sugar and protein - a slow and steady release of energy.
Other things that influence the glycemic index of food:
Cooked or processed food tends to be higher GI.
Read your labels - anything that ends in "ose" is a pure form of sugar (fructose, glucose, maltose, galactose, lactose, etc.).
The more ripe a fruit is, increases the GI
How long a food is cooked (al dente pasta has a lower GI)
So, lower GI foods are better at keeping your blood sugar levels stable because they don't increase your blood sugar level as fast. This does not mean that I’m recommending you eat M&Ms, but it is helpful to include fiber, protein and fat with higher GI foods to keep you (and your kids) on an even keel.
FUN 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 and arguably, more important to overall health.
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. This is actually more important as it is directly related to disease.
A low GL score means the food causes a lower and steadier increase in blood sugar. A high GL score means the food causes a higher and faster spike in blood sugar. And what goes up, must come down.
Low GL would be 0 - 10, moderate GL would be 10-20, and high GL would 20+.
GL also depends on numerous factors:
The amount and type sugar in the food
How much of the food you eat
Fiber, fat and protein content
How the food is prepared
Foods on the lower GL scale include fruits, vegetables, dairy, wholegrain breads.
On the high end, you find juices, dried fruit (raisins, craisins, etc.), potatoes, bagels, spaghetti, white rice, refined breakfast cereals, chips, French fries and candy.
Example of GL and GI
So, let’s compare average (120 g) servings of bananas and oranges. Please keep in mind, these are two very healthy foods. I simply want to demonstrate how 2 similar foods can have a different impact on the body.
Harvard Health reports ... An orange and a banana both have the GI score around 46 (orange = 45 and banana = 48). The serving size is exactly the same (120g), but the banana has a GL score of 11 whereas the orange comes in at 5. They also have the same amount of fiber (2.5g/100g).
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). Why? The banana contains more sugar per serving than the orange. Of course, this is all relative. A GL of 11 is not high at all. Please keep eating whole fruits. :) But it does show you two similar foods can have a different impact on your blood sugar levels.
What does this all mean for your health?
Every time you eat a food that spikes your blood sugar, you also spike your insulin. Foods that enter the blood stream quickly + inactivity = fat storage and then "a sugar crash" that fuels your carb cravings all over again.
Another example ... you eat a high glycemic meal for breakfast (bagel, cereal, toast) and release a bunch of sugar quickly into your system. Sugar is meant to fuel the body's movement, action, exercise. The problem is, you're not moving. You're sitting in your car or at your desk.
So, your body is flooded with sugar from the high GI meal it just received. Insulin jumps into action. It shuttles what it can into the muscles that need it for movement, and then it stores the excess sugar as fat. This happens quickly. Your blood sugar drops and then you are left craving something higher GI all over again.
This repeated pattern fatigues the body - insulin basically "just gets tired" of doing all the work, and the cells in your body stop listening.
Certain people should be aware of the effects that foods have on their blood sugar. If your doctor has told you that you're overweight or at risk of pre-diabetes, insulin resistance, type 2 diabetes or heart disease, you need to be aware of the glycemic index and glycemic load of foods you are eating regularly.
The 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, have them with a high-fiber, fat or protein food.
If you're interested in learning more about how to change diet to better manage blood sugar, try my free 5-day carb curving challenge, starting September 10th.