In technical terms the glycemic index of foods is determined by how they immediately influence blood sugar levels in the body when we eat them. So, what exactly does that mean? Think of a water balloon. If you were to drop a balloon from a high building the balloon would be broken quickly on impact and a “gush” of water would be released. In the body foods with a high glycemic index are quickly digested and broken down resulting in a high, fast blood sugar response.

If you were to take the same balloon and drop it from a low height and a stone pierced a small hole in the balloon the water would  “dribbles” out. Similar to this balloon, foods with low glycemic indexes are slow to digest and breakdown. This results in a slow but gradual release of glucose into the bloodstream.

A GI of 70 or more is high, a GI of 56 to 69 inclusive is medium, and a GI of 55 or less is low.

For memory sake we can think of high glycemic index foods as “bursters or gushers” and low glycemic index foods as “drippers.”

The glycemic load (GL) gives a fuller picture than does glycemic index alone. A glycemic index tells you how rapidly a carbohydrate turns into sugar but it doesn’t tell you how much of that carbohydrate is in a serving of a certain food. To know the full effect on blood sugar it is important to know the glycemic index and load.

For example the carbohydrate in watermelon has a high glycemic index BUT per serving there is not a significant amount so the glycemic load is low.  To calculate glycemic load the quality of a carbohydrate in a given food (glycemic index) is multiplied by the amount of carbohydrate in a serving of that food. By knowing both values we have a better indication on how a carbohydrate food will affect blood sugar.

Which of these is more important for people like diabetics, or those who want to lose weight, to consider?

Knowing both GI and GL allows a nine component grid to be created low GL with low, med, hi GI, Med GL with low, med, hi GI, and High GL with low, med high GI. Careful and accurate interpretation of glycemic effect of food therefore necessitates a understanding of both glucose load and glycemic index.

The type of foods we consume dictate what your body is going to burn as fuel to survive and what it is going to store as body fat. The aim of weight loss is to burn muscle and release body fat. Low glycemic foods as beneficial in weight loss as the body tends to use fat for fuel instead of relying on muscle. Foods that are low in glycemic index are also advantageous for weight loss because they fell to make you feel full faster and for longer.

Is it possible for foods to be high in one, but not the other?

Actually yes!

The carbohydrate in watermelon, for example, has a pretty high GI (about 72), but there isn’t a lot of it, so watermelon’s glycemic load is relatively low.

To calculate glycemic load, glycemic index is divided by 100 multiplied by its available carbohydrate content (i.e. carbohydrates minus fiber) in grams.

Example: Watermelon 100 gram serving has about 8 grams of available carbohydrate.

Glycemic load, therefore:  72/100*8 =5.04, rounded to 5.

A GL of 20 or more is high, a GL of 11 to 19 inclusive is medium, and a GL of 10 or less is low.

Thus watermelon has a high glycemic index but because few carbohydrates are available per serving the glycemic load is low. Careful and accurate interpretation of glycemic effect of food therefore necessitates a understanding of both glucose load and glycemic index.

How can people easily keep track of/monitor GI and GL?

Take advantage of technology. There are many aps out there that track GI and GL quickly and efficiently. Some examples are “Glyndex ”, “Glycemic Index and Glycemic Load”, “ Glycemic Index & Load Diet Aid”, and “Low GI Diet Tracker.” It is all about first finding an app that is compatible with your device but most importantly one that you will actually use.

Is stress the missing component to insulin resistance?

There is new evidence to suggest diet and exercise are not the only factors we can target to improve insulin resistance and diabetes.  Evidence shows cortisol directly triggers a physiological hyperglycemia and psychological stress is therefore identified as a chief determinant in the development of visceral adiposity and insulin insensitivity. In one study Stress from work predicted 125% increased risk metabolic syndrome (3 major events versus none over a 14 year period). Chandola. BMJ. 2006;332: 521-25.*

References:

Chandola, T. “Chronic Stress At Work And The Metabolic Syndrome: Prospective Study”. BMJ 332.7540 (2006): 521-525. Web.

“Diabets.Org”. Diabets.org. N.p., 2016. Web. 17 May 2016.