In the world of nutrition, there have been a number of words and phrases that have stumped even the savviest of those in the nutritional "know". Whether you've scratched your head trying to figure out the difference between pro and pre-biotics, or driven yourself mad trying to keep track of which omega fat does what, or goodness me, if 100% whole wheat is considered a whole grain, you've probably felt like throwing in the nutrition towel once and for all!
While I know its difficult to navigate through today's linguistic labyrinth of nutritional lingo, I can offer a small consolation in the form of clarifying one particularly perplexing concept: the glycemic index. Put those thinking caps on because it's now time for a "sweet" little lesson, nutrition style!
The glycemic index (GI) is a method of classifying the effect that a particular carbohydrate has on blood sugar. When we eat breads, pastas, or even fruits and vegetables, our bodies break down the carbohydrates found in these foods to glucose, our main source of fuel. However, not all carbohydrates are created equally. Some foods contain simple carbohydrates that are broken down rapidly, which floods the bloodstream with glucose. Commonly referred to as a high glycemic response, this can cause a dramatic spike in blood sugar levels, followed by a rapid decline as a large amount of insulin (a hormone that removes glucose from our blood) is secreted from the pancreas to deal with the sugar overload. Think of this as the ultimate crash and burn as far as nutrition goes.
On the other hand, some foods contain complex carbohydrates that are broken down much slower. The result: these foods have a low glycemic response because glucose is released at a more gradual pace. This also produces a less exaggerated insulin response from the pancreas. For diabetics, or those who struggle with satiety while trying to lose or control weight, these low glycemic foods may be a better option. Research has shown that consistently eating low glycemic foods may also help to regulate hunger, reduce overeating, prevent heart disease and type 2 diabetes, and improve the way our bodies metabolize fats.
Now that we've gotten the science out of the way, you're probably wondering (and more interested in) what foods are considered low, medium, and high on the glycemic index. Foods are given a number out of 100, which ranks their propensity to raise blood sugars. Here's a brief aside for all you die-hard scientists: the number 100 is the glycemic value of pure glucose, so the number assigned to a particular food is a direct comparison to glucose. White and whole-wheat breads, donuts, waffles, cornflakes, carrots, ripe bananas, and many dried fruits are considered high glycemic foods because they have glycemic index values of 70 and above. Foods such as basmati and brown rice, new/white potatoes, oatmeal, and quick oats are classified as medium glycemic foods with values between 56 and 69. Low glycemic foods are those with values of 55 and below and include bulgar, barley, lentils, pasta, and apples.
Hang on because the GI lesson isn't over just yet. You may be shocked to know that not all low glycemic foods are healthy for you. Case in point: ice cream. Surprisingly, many ice creams have low to moderate glycemic index values. Before heading out to your favourite parlour, I must warn that the high saturated fat and sugary decadence of this creamy treat hardly makes it a healthy choice by any standard. A similar quandary exists amongst the high-glycemic group of foods. Although whole-wheat breads, carrots, and dried fruits are considered to have high glycemic values, they do provide valuable nutrients in the form of fibre, iron, and other important vitamins and minerals that our bodies need.
As we near the end of our lesson, keep in mind that while eating an entirely low glycemic diet may seem to be a good idea in theory, balance and some good old-fashioned culinary gumption ultimately triumphs in practice. Therefore, it is important to consider factors such as calories, protein and fat content, or vitamin/mineral composition in addition to the glycemic index of a food when planning your meals. For example, fresh, unprocessed foods like fruits and vegetables and whole grains are often lower on the glycemic index, while being naturally low in calories and fat. Try to include lentils, barley, and coucous more often in your diet as these foods have low GI values but also contain fibre, protein, and other important nutrients. And finally, when eating foods that have higher GI values, please remember 2 of nutrition's timeless truths before you nosh: portion control and moderation. If you fail to do this, you may just wind up on the not so sweet side of life.
Click to read Part 2: Sweat Side of Life
About Renee Hughes:
Renee Hughes holds a Master of Health Science in Nutrition Communication from Ryerson University in Toronto. She also holds a Bachelor of Applied Science in Food and Nutrition from Ryerson University and a Bachelor of Arts in Crime and Deviance from the University of Toronto. As a passionate nutrition and food writer, Renee has written articles for dietitians, non-profit agencies, and has developed community based nutrition workshops in Toronto. To contact Renee, please send an email to: firstname.lastname@example.org