Low Glycemic Diets: Effective for Weight Loss?

low glycemic diet for weight loss
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Many dieters use a low glycemic diet for weight loss. They don't count calories, skip dessert or measure small portions, but simply choose carbohydrates based on their glycemic load in order to slim down. But is that an effective method of weight loss? If you're considering a low glycemic diet to lose weight, learn more about the pros and cons of this program before you decide what's best for you.

What is Glycemic Index?

The glycemic index (GI) is a rating system that evaluates a food's effect on your blood sugar levels over time. Foods that contain carbohydrates are tested and ranked on a scale of 1-100. Low glycemic foods are generally foods that have a GI value of 55 or under.  High GI foods have a value of 70 or more.

Foods that are low on the glycemic index are believed to be foods that enter your bloodstream slowly and keep your blood sugar levels steady to prevent overeating. Foods that are high on the glycemic index, on the other hand, are foods that are believed to give you a rapid spike in blood sugar followed by an energy dip where you might be tempted to eat again.

If you are thinking about going on a low glycemic diet, you'll need to choose the foods that you eat based on their GI rating. Some dieters look for a GI symbol on the foods that they purchase to make the best low glycemic index choices.

But not all low glycemic foods carry the symbol, so you generally have to do a little legwork to find each food's value.

To get the glycemic index rating of foods, many dieters use the online searchable University of Sydney database.  Many others use the Harvard University list, which provides both the glycemic index value along with each food's glycemic load.

Glycemic load is a number that factors in both the GI value of a food and the suggested serving size

Science Behind Low Glycemic Diets

Unfortunately, the science behind low glycemic diets can be confusing. First, the popular belief that glycemic index can can distinguish between "fast sugar" foods and "slow sugar" foods may be wrong. Several studies have found that long-held belief - on which many diets are based  - to be inaccurate. In addition, the clinical studies about the effectiveness of low glycemic diets for weight loss and maintenance are inconsistent.

One recent study published by JAMA found that low-glycemic diets helped overweight individuals maintain weight loss with greater ease than other diets. But this small study only evaluated dieters in a very controlled setting where foods were pre-selected and provided to the participants. In a real-world setting choosing the right foods is more complicated - and therefore may be more stressful.  Other studies have found that low glycemic diets don't provide consistent weight loss results.

Low Glycemic Diets: The Bottom Line

Time and time again, researchers find that the diet that works is the diet that you are willing to stick to. If you are using a healthy low glycemic diet and you're losing weight, there's no reason to change your program. But if you are trying to find the best diet for you, take into account both the work that is required to find low glycemic foods and the inconsistent clinical results before you make a final decision.


J G Aller, et al . "Weight loss maintenance in overweight subjects on ad libitum diets with high or low protein content and glycemic index: the DIOGENES trial 12-month results ." International Journal of Obesity.  March 2014.

Amin Esfahani, et al. "The application of the glycemic index and glycemic load in weight loss: A review of the clinical evidence ." IUBMB Life  January 2011.

Cara B. Ebbeling, PhD., et al "Effects of Dietary Composition on Energy Expenditure During Weight-Loss Maintenance ." Journal of the American Medical Association  June 2012.

Thomas Meinert Larsen, Ph.D., et al "Diets with High or Low Protein Content and Glycemic Index for Weight-Loss Maintenance ." The New England Journal of Medicine  November 25, 2010.

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