Experts disagree regarding the use of the glycemic
index in athletes’ diets and in exercise performance.
Insufficient evidence exists supporting the benefit of
low glycemic meals prior to prolonged exercise. None-
theless, a low GI pre-event meal may be beneficial for
athletes who respond negatively to carbohydrate-rich
foods prior to exercise or who cannot consume carbo-
hydrates during competition. Athletes are advised to
consume carbohydrates of moderate to high GI dur-
ing prolonged exercise to maximize performance,
approximately 1 gram per minute of exercise. Follow-
ing exercise, moderate to high GI foods enhance gly-
cogen storage.Precautions
If an individual has health concerns, a low glyce-
mic index diet should be undertaken with the super-
vision of a doctor. Doctor supervision of the GI diet is
not necessary when the individual is healthy and dis-
ease-free. People with diabetes should consult an
endocrinologist, who may recommend discussing the
diet with a diabetes dietitian.Risks
Eating a diet based solely on the glycemic index of
foods can lead to overeating and a weight gain rather
than loss. No emphasis is placed on total calorie intake
or on the amount of saturated fat content. By basing
one’s diet on glycemic index alone, it is still possible to
eat excess calories and to, therefore, gain weight.Research and general acceptance
There is mixed acceptance of glycemic index diets
by the medical community. Some studies have shown
GI diets can be effective in controlling blood sugar
levels in diabetics and in helping people lose weight.Other studies have contradicted these findings. No
major studies or research has shown that GI diets are
harmful to a person’s health. The American Diabetes
Association has adopted a position that there is not
enough conclusive evidence to recommend the general
use of a low-GI diet for diabetics. Not all physicians
and endocrinologists (medical specialists who treat
disorders of the glands, including diabetes) subscribe
to the association’s position.
In 2006, researchers at the University of Sydney
(Australia) found that low-carb, low-GI diets
decreased fat mass and reduced the risk of cardiovas-
cular disease.Resources
BOOKS
Beale, Lucy, and Joan Clark.The Complete Idiot’s Guide to
Glycemic Index Weight LossNew York: Alpha-Pen-
guin, 2005.
Brand-Miller, Jennie, et al.The Low GI DietLondon: Hod-
der Mobius, 2005.
Elliot, Ross.The Vegetarian Low-Carb Diet: The Fast, No-
Hunger Weightloss Diet for VegetariansLondon: Piat-
kus Books, 2006.
Gallop, Rick.The G.I. Diet: The Easy, Healthy Way to
Permanent Weight LossNew York: Workman Pub-
lishing Company, 2003.
Scales, Mary Josephine.Diets in a NutshellClifton, VA:
Apex Publishers, 2005.
Sears, Barry, and Deborah Kotz.A Week in the Zone: A
Quick Course in the Healthiest Diet for YouNew York:
Regan Books, 2004.
PERIODICALS
Blitz, Peggy, and Lori Hoolihan. ‘‘Low Glycemic Index
Diets: Separating Fact From Fiction.’’Dairy Field
(March 2006): 53–54.
Brand-Miller, Jennie, et al. ‘‘Meta-Analysis of Low Glyce-
mic Index Diets.’’Nutrition Research Newsletter(Sep-
tember 2003): 7–8.
Freeman, Janine. ‘‘The Glycemic Index Debate: Does the
Type of Carbohydrate Really Matter? ’’Diabetes Fore-
cast(September 2005): 11.
Helm, Janet. ‘‘Taking a Bite Out of the Glycemic Index
Trend.’’Chicago Tribune(December 23, 2005):N/A.
Kuritzky, Louis. ‘‘Low-Glycemic Index Diets and Diabetes.’’
Clinical Cardiology Alert(November 2003): S21–S22.
MacReady, Norra. ‘‘Glycemic Index Key to Many New
Diets: What Patients Are Reading.’’OB GYN News
(October 1, 2003): 1–2.
Moon, Mary Ann. ‘‘High-Carb, Low-Glycemic Index Diet
Cuts Weight, Cardiac Risk.’’Family Practice News
(September 1, 2006): 15.
Shute, Nancy. ‘‘The Scoop on Carbs and Fats.’’U.S. News &
World Report(November 20, 2006): 89–90.QUESTIONS TO ASK YOUR
DOCTOR What dietary supplements should I consider
taking while following a GI diet?
What are the health risks of this diet?
What other diets would you recommend I
consider to help me accomplish my weight loss
goals?
Have you treated other patients who are on a
glycemic index diet? If so, what has their
response to the diet been?Glycemic index diets