You may have heard the term “low glycemic” in the media and in discussions about weight loss, but Dr. Atkins was on to it many decades ago. With Atkins, it’s easy to know which foods have the lowest glycemic impact.
It’s All About Sugar
“Glycemic” simply means “relating to sugar.” The higher the glycemic impact of a food (more about this below), the greater and more rapid its effect on your blood sugar when you eat it—and the more insulin required to return your blood sugar to normal. Since insulin is a fat-storage hormone and since overweight people often already produce too much of it, high blood sugar and high insulin can sabotage your weight-loss efforts. Eating lower glycemic foods is definitely the way to go.
Atkins has always been a low-glycemic approach. Almost 40 years ago, Dr. Atkins stressed the effect of food on blood sugar and insulin levels and explained in great detail why foods with a significant impact on blood sugar—meaning processed carbohydrates—were exactly what you don’t want on your plate, whether you’re concerned with your weight or your health.
But how do we measure the glycemic impact of foods containing carbs? And how does that translate into deciding what to eat and what to pass up?
The Glycemic Index…
The first ranking, known as the glycemic index (GI), measured the relative impact of carbohydrate foods on blood sugar. The GI of a particular food is determined by comparing the effect of a 50-gram portion on blood sugar to that of a 50-gram standard such as a glucose solution or white bread. 1 The higher a food’s GI, the faster and greater its effect on your blood sugar. Although the connection between high-sugar diets and obesity and diabetes has been obvious for some time, research has also shown a connection between high-glycemic diets and both cardiovascular disease and cancer. 2,3,4
…And Its Limitations
The GI does not take into account the portion size you actually eat. Carrots, for example, have a very high GI rating for the standard 50-gram portion, which could comprise 3 cups, or 6 servings, of carrots. But you’d never eat such a large portion of carrots. There are only about 3 or 4 grams of Net Carbs in a carrot, so assuming you eat one or two servings of carrots at a sitting, the GI alone significantly overestimates this food’s glycemic impact. Pasta, on the other hand, has a moderate GI rating, but a 50-gram portion of pasta, which is about one-third of a cup, is hardly a typical portion—in most restaurants you’d be served six times that. In the case of pasta, the GI significantly underestimates the “real-life” effect on your blood sugar. Because the GI does not take into consideration portion size, Dr. Atkins didn’t recommend using it as the sole way to determine which foods to eat. The GI simply doesn’t reflect our actual eating habits.
The Glycemic Load
The glycemic load (GL) improves on the measuring process of the GI. Because it does take portion size into account, it gives a more accurate reading.
Selected References
1 Foster-Powell, K., Holt, S.H., Brand-Miller, J.C., “International Table of Glycemic index and Glycemic Load Values: 2002.” Am Journal of Clinical Nutrition , July, 2002;76(1):5-56.
2 Dickinson, S., Brand-Miller, J., “Glycemic Index, Postprandial Glycemia and Cardiovascular Disease.” Current Opinions in Lipidology , 16 (1), pages 69-75, 2005.
3 Brand-Miller, J.C., “Glycemic Index in Relation to Coronary Disease.” Asia Pacific Journal of Clinical Nutrition , 13(Suppl), page S3, 2004.
4 Michaud, D.S., Fuchs, C.S., Liu, S., et al, “Dietary Glycemic Load, Carbohydrate, Sugar, and Colorectal Cancer Risk in Men and Women.” Cancer Epidemiology Biomarkers Prevention , 14(1), pages 138-147, 2005.
