Complex versus Simple or Processed Carbohydrates – Part 3

In continuing parts one and two of this series, part three will further discuss why all foods are not equal in how they affect blood sugar levels and subsequent insulin spikes. Glycaemic Index (GI) and Glycaemic load (GL) provide insight into these effects. The glycaemic index assigns a numeric score to a food based on how much it increases your blood sugar level. The lower a food’s glycaemic index, the slower blood sugar rises after eating that food. Carbohydrate-containing foods can be classified as high- (≥70), moderate (56-69), or low (≤55) GI relative to pure glucose (GI=100). Generally, the more processed a food is, the higher its GI and the more fibre in it, the lower its GI. It should be noted that while healthy food choices generally include low-GI foods, this is not always the case.

To understand a food’s full effect on blood sugar, you need to know both how quickly it makes glucose enter the bloodstream and how much glucose per serving it can deliver. A separate measure called the glycaemic load (GL) does both, giving you a more accurate picture of a food’s real-life impact on your blood sugar. Because the GL of food looks at multiple components, the same food can be high on GI but carry an overall low GL. In these cases, this food is a better choice for blood sugar management. For example, watermelon has a high GI (80). But a serving of watermelon has so little carbohydrate that its GL is only 5 (PS. there are free apps that let you easily search for and display the GL for different foods). GL is classified as:
• Low GL: 10 or less
• Medium GL: 11 to 19
• High GL: 20 or higher

The Glycaemic Index Foundation recommends keeping your daily GL under 100 and spread equally over the day for optimal health.

A study found that participants with poorly managed diabetes, who were on insulin or oral diabetes medications, and followed a low GL diet for ten weeks lost weight, lowered their cholesterol levels, and improved their average blood sugar levels. Other studies found that low GL diets, regardless of calorie restriction, were more helpful with weight loss than the conventional, low-fat diets in reducing body weight.

Lowering dietary GL can be achieved by increasing the consumption of whole grains, nuts, legumes, fruit, and non-starchy vegetables and decreasing intakes of high-GI foods like potatoes, white rice, white bread, breakfast cereals etc. and all sugary foods.