The Hoax of the Glycemic Index
By Erik Ledin
The Glycemic Index, the GI; whatever you want to call it, most of us have heard it. We’ve heard about it from ‘experts’, from the mainstream media, from friends who just read an article somewhere, from established health organizations and who knows where else. Point being, the concept of the Glycemic Index isn’t one most of us haven’t heard about before.
However, is it relevant? To those of us with physique-conscious pursuits?
Do people even know what it actually is? Most of us assume that it’s a measure of ‘carb quality’ for lack of a better term. In actuality, it’s commonly described as the dietary carbohydrate derived rate of glucose entry into the blood. So by definition, those foods that fall lower on the Glycemic Index are said to enter the bloodstream slower and subsequently raise blood sugar slower than those foods which fall higher on the Glycemic Index. However, more recent research has suggested that the disappearance rate of glucose from general circulation is also an important factor determining the glycemic index of a given carbohydrate. For example, a very rapid insulin response would result in a quicker system-wide circulatory disappearance of glucose, resulting in a lower glycemic index value.
What most people seem to forget is how the Glycemix Index figures came to be. People automatically assume that if you eat potatoes (yep, those ‘bad-for-you white potatoes) that you might as well just eat sugar. Or worse, fat loss will stop dead in its tracks. You’ll never get ripped with white potatoes. Again, what people either don’t know or seem to forget is that the parameters used to determine each food’s glycemic index is based on a test of 50g of that given carbohydrate eaten by itself after an overnight fast.
Take note of the last part – by itself after an overnight fast. Those two conditions right there dramatically reduces the relevance and applicability of the Glycemic Index numbers. Think about it – who eats that way? I don’t know anyone who routinely eats 50g of carbohydrates at a sitting with nothing else. Not to mention the overnight fast. Why is this important? Because the addition of other food stuffs changes the GI value of a given carbohydrate. How? Quite simply it generally decreases it, which means that it slows down the rate of digestion and subsequent entrance of glucose into the blood. Things like fat, protein, and fiber – a normal mixed meal – all function to reduce gastric emptying and subsequently, the stated GI of a given carbohydrate. As well, digestion of previous meals also presents quite a different digestive set of circumstances than does an overnight fast.
→ NEXT: Read on to find out what else affects the Glycemic Index and about something called the Insulin Index.
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Find out about Erik Ledin, Certified Strength and Conditioning Specialist (CSCS), Certified Sports Nutritionist (CISSN), Certified Kinesiologist (CK), Certified Personal Trainer (NSCA-CPT)