Glycemic Impact Diet
The glycemic impact diet is based on the glycemic index GI which measures the effect of foods on the blood sugar level. Foods with a high GI value, such as white sugar and flour, will raise the blood sugar level more than foods with a low glycemic index value, such as vegetables and whole grains. Foods with a low GI value slowly release sugar into the blood, providing the body with a steady supply of energy, and leaving us feeling satisfied longer, while foods with a high GI value cause a rapid, short-lived rise in blood sugar with the result that we are hungry again within a short time.
How Does The Glycemic Impact Diet Work?
The GI values are measured from 1 to 100 with pure glucose having a value of 100. 70 or more counts as high, 56 to 69 is medium, and 55 or less counts as low. The glycemic impact diet further uses the glycemic load GL of a food to determine quality carbohydrates. GL is a relatively new way to assess the impact of carbohydrate consumption. The GL of a food is calculated by multiplying the GI by the amount of carbohydrate in grams provided by a food and dividing the total by 100. Generally, each unit of the GL represents the equivalent blood glucose-raising effect of 1 gram of pure glucose. Scientists developed the concept of GL to describe the quality (GI) and quantity (GL) of carbohydrate in a meal. A GL of 20 or more is high, a GL of 11 to 19 is medium, and a GL of 10 or less is low.
For example, while most candy has a high GI, eating a single piece of candy will result in only a small glycemic response, because the glycemic response depends on both, the type and the amount of carbohydrate consumed.
Some Examples of Glycemic Indexes and Glycemic Loads
A medium sized apple has a GI of 38 and a GL of 6.
A large carrot has a GI of 47 and a GL of 2.
A large banana has a GI of 52 and a GL of 14.
100 grams of bean sprouts have a GI of 25 and a GL of 1.
100 grams of potatoes hav a GI of 50 and a GL of 9.
1 slize of white bread has a GI of 70 and a GL of 10.
4 oz of potatoe chips have a GI 54 and a GL of 30.
4 oz of peanuts have a GI of 14 and a GL of 2.
Pros and Cons of Glycemic Impact Diet
Although GI and GL are good tools for ranking carbohydrates, they also have their limitations. It is not always possible to measure the exact GI of a certain food and measurements can vary significantly. The GI changes with different food preparations and the value for one food is affected by the combination with other foods. The rate at which different people digest carbohydrates varies and if GI and GL values are used as the sole factor for determining our diet, we can end up overconsuming fat and total calories. For example, a medium sized apple has a GI of 38 and provides a GL of 6. This is a low GL and makes the apple to be a very good snack. But if we look at peanuts, we see that a 4oz-serving has a only a GI of 14 and provides a GL as low as 2. Based on GL alone, we would have to believe that the peanuts were a better dietary choice than the apple. But if we take a look at the calories contained in these two foods, we will see that the apple contains approximately 72 calories, while the peanuts contain more than 500. These 400 extra calories are not going to help us lose weight.