Balancing Your Blood Sugar with the Glycemic Index
In the body, all carbohydrate-based foods—such as sugar, grains, beans, vegetables, and fruit—convert primarily to glucose, or “blood sugar.” But different foods break down to blood sugar at very different rates. For example, sugary or starchy foods, such as white bread and pasta, table sugar, and very sweet fruits like bananas and pineapple, convert to glucose quickly (and so they raise your blood sugar rapidly), while whole grains, beans, and non-starchy vegetables such as broccoli or green beans break down more slowly (and so glucose gets to your blood at a slower clip).
The glycemic index (GI) is a scale that ranks how quickly a food’s carbohydrates raise your blood sugar level after eating it. The scale ranges from 0 to 100, with lower scores indicating foods that convert to blood sugar slowly and higher scores indicating foods that become glucose in your blood quickly. Generally speaking, the higher a food ranks on the index, the greater its effect on spiking your blood sugar level. And since blood sugar spikes lead to energy crashes, limiting high-glycemic foods is critical for anyone looking to balance their energy through diet.
Sugar and Starch
While many people instinctively understand that sugary foods such as candy and soda have high GI values, a less obvious cause of high GI scores is starchiness. That is, foods such as pasta, bread, bagels, breakfast cereal, pretzels, rice, potatoes—which all contain high amounts of starch—tend to convert to blood sugar rapidly and cause energy spikes and crashes. On the other hand, foods that contain little or no starch, such as meat, fish, nuts, cheese, fats, and non-starchy vegetables (leafy greens, peppers, cucumber, green beans, tomato, broccoli, cauliflower, asparagus, etc.) are all “low glycemic” and a boon to anyone looking to maintain balanced energy.
Of course, most people do not want—nor need—to avoid starch altogether. Fortunately for them, it’s easy to get a sense for which starchy foods rank highest on the glycemic index. They’re usually the ones that are highly refined. Almost always, the more processed or refined a starch is, the higher its value on the glycemic index—as, for example, with white wheat flour or corn flour or white rice flour. (This is very important for people avoiding gluten to remember because most gluten-free products contain highly refined non-wheat grain flours that have very high GI values.)
Anyone who’s ever eaten a stack of pancakes made with white flour drizzled with sugary syrup knows precisely the energy crash of a highly refined, high-glycemic meal!
A Step Further: The Glycemic Load
While glycemic index tells us how quickly a food’s carbohydrates become blood sugar, it doesn’t reveal anything about the amount of carbohydrates in a typical serving of the food. For example, a whole bagel and a slice of watermelon both have a high GI value, but the bagel has a lot more carbohydrates. And all those carbs are going to have a more drastic effect on your blood sugar than the much fewer carbs in the watermelon—even though the carbs in each food convert to glucose equally quickly.
To reflect the carbohydrate amounts in typical portions of different foods, scientists created the glycemic load. This basically shows the glycemic index for a food weighted by how many carbs are in a typical serving of that food. (To get a feel for the glycemic load, think about a whole baked potato versus half a baked potato: they have the same glycemic index, but the whole potato has twice the carbs, so its glycemic load is twice as much.) In short, the glycemic load gives us a better idea of how foods affect blood sugar in the typical amounts they are eaten.
If all of that sounds too technical, never fear! If you’re looking to balance your blood sugar using the glycemic index, simply remember these basic rules:
Glycemic Tips for Balancing Blood Sugar
- Foods low in starch and sugar (meat, eggs, nuts, fats, whole-fat dairy products, non-starchy vegetables) have minimal effect on your blood sugar. So, to maintain good energy, make them the foundation of your diet.
- When it comes to starchy foods (grains, beans, root vegetables), choose whole over processed. For example, cooked brown rice over a rice cake; corn on the cob over a corn tortilla; steel cut oats over instant oats; etc.
- For grain foods, the more refined they are, the higher their glycemic index. (So choose sprouted-grain bread over white bread, for instance, or brown-rice pasta over white-rice pasta.)
- Think about the relative amount of the food you’re eating. Obviously a bowl of pasta is going to affect your blood a lot more than a couple of carrot sticks or beet slices, even though all these foods have high glycemic index values.
- Some fruits (berries, apples) have much less sugar (and therefore a much lower glycemic effect) than others (bananas, pineapple, mango).
- Fiber, fat, and protein slow the absorption of carbohydrates. So if you’re going to have a high-glycemic food, eat it after you’ve eaten these foods. For example, have a piece of fruit after a lunch of chicken salad on sprouted wheat bread or some dark chocolate after a stir fry of beef and broccoli.