Glycemic Index and Weight Loss

Experts disagree on the connection between a high or low GI diet and weight loss.
Glycemic Index and Weight Loss

The use of Glycemic Index, or GI, as a meal-planning tool appears to be beneficial in the treatment of diabetes and high cholesterol levels.1 There is also limited evidence that a high GI diet may be associated with development of obesity and some forms of cancer.2

Effect of a Low GI Diet
Theoretically, using GI as a weight-loss method makes a lot of sense. Several short-term studies indicate that a low GI diet creates a feeling of fullness, delaying the return of hunger following a meal.3 The effect of a low GI diet in reducing the body's production of insulin is also widely recognised. And a low GI diet may favourably affect the resting metabolic rate, represented by the calories used to keep the body's systems going, when compared to a low-fat diet.4

Considering the theoretical potential of GI as a weight-loss method and the known health hazards of continued overweight, some experts favour recommending low GI diets for weight loss now.5

Other experts disagree because the majority of studies that have specifically compared a low GI diet and a high GI diet have not shown a better weight loss following the low GI method. In 20 studies, each lasting less than six months, a superior weight loss on a low-GI diet was seen in four and on a high-GI diet in two others. There was no difference in the amount of weight loss in the remaining 14.6

In another study designed to evaluate the impact of encouraging low GI foods as part of the Weight Watchers food plan, no significant difference in weight loss was found, although there were significant differences in the reported feelings of hunger and satiety.7

More Studies Underway
The ideal long-term study to evaluate the effectiveness of GI as a sole weight-loss method has not yet been completed. Several studies are underway and the results will be released over the next few years. As these studies are completed, the understanding of what, if any, role that GI can play in promoting weight loss will be improved.

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Other Science Library Topics:

1Opperman AM, Venter CS, Oosthuizen W, Thompson RL, Vorster HH. Meta-analysis of the health effects of using the glycaemic index in meal-planning. Br J Nutr. 2004 Sep;92(3):367-81.

2Brand-Miller JC. Glycemic load and chronic disease. Nutr Rev. 2003 May;61(5 Pt 2):S49-55.

3Roberts SB. Glycemic index and satiety. Nutr Clin Care. 2003 Jan-Apr;6(1):20-6.

4Pereira MA, Swain J, Goldfine AB, Rifai N, Ludwig DS. Effects of a low-glycemic load diet on resting energy expenditure and heart disease risk factors during weight loss. JAMA. 2004 Nov 24;292(20):2482-90.

5Pawlak DB, Ebbeling CB, Ludwig DS. Should obese patients be counselled to follow a low-glycaemic index diet? Yes. Obes Rev. 2002 Nov;3(4):235-43.

6Raben A. Should obese patients be counselled to follow a low-glycaemic index diet? No. Obes Rev. 2002 Nov;3(4):245-56.

7Bellisle F. (publication pending).