Benefits of low GL diets

Diets with a low glycemic load (GL) are associated with reduced risk for cardiovascular disease and diabetes, and favorable effects on serum triglycerides and HDL cholesterol levels. There is also evidence that low carbohydrate diets can support weight loss, and consumers have interest in low carbohydrate products to help them adhere to these diets.

Low carbohydrate foods are not suitable for glycemic index testing

The glycemic index, a measure of a food’s ability to raise blood glucose levels, can only be determined in foods containing at least 10 g of available carbohydrate per serving. The methodology is not suitable for foods that are low in carbohydrate.

Equivalent Glycemic Load

Our team at INQUIS, led by Dr. Thomas Wolever, developed a method to measure the glycemic impact of low carbohydrate foods. First published in 2006, this methodology was termed Equivalent Glycemic Load (EGL). EGL is defined as the amount of available carbohydrate from white bread that raises blood glucose to the same extent as one serving of the test food. The EGL method is valid across the range of 0-20 g available carbohydrate, accurate to within 1 g and at least sensitive enough to detect a glycemic response elicited by 3 g oral glucose.

EGL testing has become the methodology of choice for food and ingredient companies who wish to demonstrate the effect of their low-carbohydrate products on blood glucose levels.

Methodology

In EGL testing, at least 12 participants consume the test food(s) or a portion of the reference food, white bread containing 20 g available carbohydrate. The participants provide finger-prick blood samples over a period of two hours. Incremental area under the plasma glucose curves (iAUC) are calculated. The EGL is a resulting value which is determined by an equation that incorporates the iAUC of the test food and the reference food and the amount of available carbohydrate in the reference food.

EGL is used to substantiate health claims relating to glucose response for low-carbohydrate foods.