Glycemic Index & The Blood Sugar Breakdown
The term "low-glycemic" refers to the glycemix index of a particular food- aka the "GI" It's a measure of the blood glucose-raising potential of the carbohydrate content of a food, compared to a reference food, generally pure glucose which clocks in with a whopping GI of 100! Carbohydrate-containing foods can be classified as high (≥70), moderate (56-69), or low-GI (≤55). In general, foods containing carbohydrates that are easily absorbed and metabolized (aka “simple carbs”) have a high GI (GI≥70 on the glucose scale), while low-GI foods (GI≤55 on the glucose scale) have slowly digestible carbohydrates (aka “complex carbs”) that cause a reduced blood sugar spike (1,2).
So, what’s happening in my body when I eat high-GI foods?
The consumption of foods deemed high-GI, result in higher and more rapid increases in blood sugar compared to the consumption of low-GI foods. This swift increase in blood sugar can lead to a condition known as hyperglycemia, which is defined as an abnormally high glucose concentration in our blood (3). Have you ever felt exhausted, thirsty, and constantly hungry or find yourself running to the bathroom to pee after a carbohydrate-heavy meal? It could be a sign that you are experiencing high-blood sugar levels, and can be an early sign that your pancreas may not be working optimally (1).
Having these elevated sugar levels in your blood acts as a powerful signal to the pancreas to pump out insulin, a hormone that helps your body turn blood sugar into energy. Although you want your body to produce insulin when you need it, a constant stream of insulin or insulin spikes can lead to an overproduction of insulin, which is known as hyperinsulinemia (3). When you’re resting, or your body doesn’t need insulin for instant energy, insulin also helps your body store glucose in your muscles, fat cells, and liver to use later, when your body needs it. Unfortunately, in people with impaired glucose metabolism (those with prediabetes, type II diabetes & PCOS for example), this chronic overproduction of insulin leads to increased storing of fat cells, particularly around your waist line and the major abdominal organs.
On the flip side of this, as your pancreas produces more and more insulin in response to high-GI foods, this excess insulin often leads to something called hypoglycemia, or “low-blood sugar.” This sharp decrease in your blood glucose can make you feel shaky, dizzy, anxious and further stimulates cravings for high sugar foods (3).
Why should I care about keeping my blood sugars stable?
Rapidly changing blood sugars not only impact our mood, energy and hunger levels, but it also can have serious impacts on many aspects of your overall health. If you have untreated hyperglycemia for long periods of time, it can cause lasting damage to your nerves, blood vessels, tissues and organs.
In contrast, constant hypoglycemia can also have detrimental effects on your health, specifically your metabolism. The more insulin the pancreas has to produce, the more this signals to your body to store sugars as fat, specifically the highly inflammatory fat that lives on your waistline (1,3). This both increases weight and levels of inflammation in the body, further working to impair the body’s ability to metabolize glucose effectively.
How can I lower my overall GI intake?
When you consume foods that are lower on the GI scale, it actually results in a more gradual, sustained increase in your blood sugar and demands less insulin to be released to combat the sugar load. This works to prevent rapid changes in blood sugars, helps to regulate mood, energy and hunger, while working to protect against complications from chronic hyper- or hypo-glycemia (1,3).
3 Simple Low-GI Friendly Swaps
- Consume non-starchy vs starchy vegetables (peas, corn & potatoes) more often (think - artichoke, asparagus, beets, broccoli, brussels sprouts, cauliflower, cabbage, salad greens). Opt for lower-glycemic fruits such as apples, pears, peaches, and berries as your standard sweet-tooth fixes. Although tropical fruits like bananas, mangoes, and papayas rank higher on the index than other lower-glycemic fruits, they still come in lower than standard desserts and are jam-packed with vitamin C!
- Incorporate whole grains more often, in the least processed state as possible. Think whole-kernel bread, brown rice, whole barley, millet, bulgur, quinoa, barley and steel cut or whole oats. In general, whole grains are higher in fiber and have less effect on blood sugar compared to refined, processed grains like white bread and pasta.
- Limit concentrated sources of sugar - these include the ones that typically come to mind (cakes, cookies, choclate bars, ice-cream), but also includes some foods that may surprise you as top offenders - dried fruit, fruit juice, maple syrup, and honey. When attempting to lower your overall glycemic index, use these sugar sources sparingly and be mindful of portion sizes.
If you’re wondering how your diet measures up on the glycemic index, both Harvard Health and the Canadian Diabetes Association have compiled helpful resources of common foods and their individual GI ratings.