Low Glycemic Index Diets May Not Lower Blood Sugar Levels – Low Carbohydrate Diets Including Atkins and South Beach Questioned

March 15th 2006

White Bread

Many dieticians recommend diets with a low glycemic index (GI), which is a measure of the effects of a given food on blood sugar levels. More accurately, the Glycemic Index (GI) is a measure of the glycemic effect of carbohydrate in a particular food compared to an equivalent amount of carbohydrate in a standard amount of glucose or white bread.

There is another factor to consider besides GI, and that is Glycemic Load (GL). The GL is the GI of the food divided by 100 and then multiplied by the grams of carbohydrate from a single serving of that food. If the specific food in consumed in small quantities a high GI may not always equate to a high GL. It may be more important to calculate the GL rather than the GI for people that need low sugar diets.

This may help explain why recent research has not been able to explain why studies have failed to find links between high-GI foods and elevated blood sugar and diabetes.

Some studies have found that diets heavy high GI foods such as potatoes and bread can contribute to weight gain, diabetes and heart disease. New research has found that it is hard to translate lab findings on glycemic index to our every day meals.

A recent report on NBC News suggests that food has different blood sugar effects when it's not eaten after a fast. Dr. Elizabeth Mayer-Davis, the lead author of a new study, points out that a food's GI is determined under “artificial conditions” where a person eats the test food after a fast, then has blood sugar tests taken two hours later. Mayer-Davis is a researcher at the University of South Carolina in Columbia.

There are other factors that can sway blood sugar levels. Dr. Mayer-Davis says that that the length of time a carbohydrate is cooked, the foods it is eaten with, and the workings of an individual's hormones, among other things may lead to results that don’t jive with lab calculations.

The research is published in the Journal of Nutrition. Her conclusion is that there was no association between high-GI eating habits and elevated blood sugar among 813 adults who were followed over 5 years.