I'm sure that you can appreciate the importance of optimizing your blood sugar levels; not only for the quest of a lean, muscular physique but, as the opening quote illustrates, the pursuit of good health and a longer life.
But considering that walking around with a glucometer and sticking ourselves after every meal just isn't practical – or polite – a more efficient method of measuring the effect of carbohydrates on blood sugar levels needed to be determined.
Sometimes though, we get lucky, and while it wasn't with the NIH, the British Diabetic Association and the Medical Research Council decided in the late 1970s to find out more about the differing effects of carbohydrate-based foods on blood sugar.
Fast forward to 1981, and the Glycemic Index (GI), a method of ranking the effects of different carbohydrate based foods on blood sugar, was born.
The GI of a food is measured in a two-step process. Researchers will give a person 50 grams of pure glucose and then measure their blood glucose levels over the course of several hours. This pure glucose serves as the control, as theoretically, nothing can be digested faster than pure glucose.
Next, researchers give the same person 50 grams of the food in question (like carrots, rice cakes, or black beans), and measure their blood glucose levels for several hours afterwards.
One key component to how the GI is measured has to do with amount. The amount of food used is always the same, 50 grams. As a result, the GI only takes into account the type of carbohydrate and not the amount. This is a point of criticism that many GI critics often bring up; for example, how practical is the GI when 50 grams of carbs from rice can be ingested with ease while 50 grams from carrots would require Bugs Bunny-like dedication?
