The glycemic index (or GI) is a ranking of carbohydrates on a scale from 0 to 100 according to the extent to which they raise blood sugar (glucose) levels after eating. Foods with a high GI are those which are rapidly digested, absorbed and metabolised (blood sugar spikes). Low GI carbohydrates produce smaller fluctuations in your blood glucose and insulin levels. Choosing low GI foods will improve your long-term health and reduce your risk of type 2 diabetes and heart disease. It is also one of the keys to maintaining weight loss because constant glucose (and insulin) spikes are very bad. When blood glucose goes up, insulin is triggered. So the insulin level in your body will fluctuate according to what you eat. The main problem with the Glycemic Index is that it does not factor in typical portion sizes., nor does it look at the proportion of carbs in the food.

The concept of GI was initially developed to help diabetes patients. It’s important for diabetics and pre-diabetics to pay close attention to their blood glucose fluctuations and insulin levels. However, everyone can all benefit from paying attention to the types of carbohydrates we eat. Whether we eat a snickers bar or a strawberry, both will be converted into glucose. What will be different, though, is how quickly this fuel enters the bloodstream.

Glycemic Load (GL)

Some carbs metabolise very quickly (such as watermelon with a GI of 72) but contain very few carbs. The watermelon only has about 5g of carbohydrate in a big slice, so is has a very low glycemic load. You would need to eat a lot to have a big impact on glucose levels. A food’s glycemic load is calculated directly from its glycemic index. We simply take the food’s GI, divide it by 100, and multiply it by the grams of carbohydrate (excluding fiber) in a typical serving size. A GL of above 20 is considered high, the 11-19 range is considered average, and below 11 is low.