Facts and Fiction Akin to the Glycemic Index

What is a Glycemic Index?

Glycemic Index or GI for short is a numerical ranking system used in measuring the comparative degree of absorption and digestion of carbohydrates and their effect on blood glucose. After consumption, a food with a low GI causes a weaker, sustained rise in blood glucose. Foods with a high GI produce a greater temporary spike in blood glucose.

A study in 1981 from the University of Toronto suggested that the GI of foods be used to classify carbohydrates instead of the traditional simple and complex carbohydrate system for the improvement of glucose control among diabetics. GI scores are classified as low (below 55), medium (56-69), or high (greater than 70).

Various situations affect the GI value of a food such as whether it is liquid or solid, the quantity of fiber, and preparation or cooking methods. The GI may also considerably differ between individuals.

What are the Similarities or Differences Between a Low GI Diet and a Low Carbohydrate Diet?

The premise behind low carb diets is that the body is forced to use fat as its main source of fuel because throughout the day, blood sugar, (or insulin level) is so low. What occurs with low GI diet plans is similar. The difference lies in low GI diets not restricting carbohydrate intake. It is just restricted in its selection of carbohydrates for consumption.

What is a Glycemic Load?

The concept of glycemic load was developed by scientists to simultaneously describe the quality (GI) and quantity of a carbohydrate in diet. The glycemic load of a food is calculated by multiplying the glycemic index by the amount of carbohydrate in grams provided by a food and dividing the total by 100. For example, the glycemic load of 2.4 ounce French fries with a GI of 54 and 21 g of carbs is GL = 54 x 21g divided by 100 = 11. The GL of a pear with a GI of 25 and 21 grams of carbs is GL = 25 x 21g divided by 100 =5. The French fries have more than 2 times the glycemic weight of a pear.

Five Glycemic Index Myths

Myth 1 -- Avoid white foods such as potatoes and white bread because they have a high GI.

Color in essence does not anticipate a high GI. Preparation method, quantity of processing and meal composition influence GI, not food colors. For instance, white bread spread with 35 grams butter (78) has more GI than white bread dipped in 35 grams of olive oil GI (20). Therefore, eating potatoes or white bread in conjunction with protein and fat changes their overall GI values.

Myth 2 -- The GI is the foremost way to establish the quantity of carbs and sugar in certain foods.

GI plainly accounts for the rate with which glucose is discharged into the bloodstream. In the above illustration, both pear and fries have uniform quantities of carb grams. However, the pear has a lower GI value. On the other hand, you may eat two foods with different carb content but similar GI values. Foods consumed in higher quantities will bring about a higher blood glucose response.

Myth 3 -- Simple sugars are all high in GI.

The GI for most raw fruit is between 30-50 even though they contain the simple sugar fructose (GI 21). Most fruit have a slower rate of absorption and digestion than glucose (GI 93) another simple sugar.

Myth 4 -- GI values can determine healthy and unhealthy foods.

The GI does not point to whether a food is healthy or not. For example, whole milk has a GI of 27 whereas skim milk has a GI of 32. In this example, lower GI doesn't constantly mean a healthier product because whole milk contains saturated fat making it a less than healthier choice.

Myth 5 -- I can eat limitless low GI food and still keep my insulin levels low.

Keep in mind that the glycemic response is a fusion of GI and carb density. Hence, higher carb consumption will still payoff in higher insulin levels even with low GI values.

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