The glycemic index is a system that calculates the effect of different carbohydrates on the body. It tells how quickly and for how long a food will supply energy (sugar) to the bloodstream. Foods with a high GI score supply energy very quickly and for a short time period. Usually, these foods should be avoided, though they can be beneficial when your glucose levels are low and need to be quickly elevated. Foods with a low GI score supply energy at a slower, steadier, and more prolonged rate. For people with diabetes, choosing low-GI foods can help keep blood glucose levels even and can prevent sharp spikes and dangerous crashes.
You can’t always guess which foods will have high or low GIs. It is easy to predict that people with diabetes should avoid too many sugary foods. But did you know that foods like white bread and potatoes have an even higher GI than sugar or honey?
Carbohydrates are ranked from 0 to 100 on the glycemic index, with 100 (the value of pure glucose) being a stable reference point.
Here are a few examples of GI scores:
Notice that pizza, a food that might be considered “bad” for you, is low on the GI scale. Why is that?
In reality, we rarely eat just one food at a time. We usually have complete meals that include fat, proteins, and carbohydrates, all of which are needed for optimal health. In general, fat, protein, and fiber will reduce the GI-rating of a food (such as pizza) because it takes the body longer to digest these more complex foods. Thus, the release of sugar (energy) into the bloodstream is delayed and prolonged.
With the glycemic index, it’ not just about the number value assigned to a food. It’s about portion size, too. If you eat a small portion of a high-GI food, you’ll get a small glycemic response. On the other hand, if eat a large amount of the same food, your glycemic response will be much more drastic. The “glycemic load” of a food is the score it is given based on the portion size, not just how quickly glucose is released to the bloodstream. When choosing what to eat, it’s important to know both numbers, the glycemic index rating and the glycemic load. Some foods with a low glycemic load (such as peanuts or popcorn) can be high in calories or have a high GI rating.
Making the Switch
The glycemic index can help you eat healthier and control your diabetes more effectively. So how can you incorporate low-GI foods into your diet? It’s easy. Start by switching one item at a time. Put that white bread back on the shelf and grab a whole-grain or sourdough loaf instead. Eat fewer potatoes and more pasta or noodles. Then, start adding more fruits and vegetables to your grocery list. Just small changes can add up quickly…to better health for you.