Correspondence

Overweight Children and Adolescents

N Engl J Med 2005; 353:1070-1071September 8, 2005

Article

To the Editor:

Although large-scale trials are needed to assess effectiveness, a diet with a low glycemic index appears promising in the treatment of childhood obesity, especially in combination with the innovative behavioral strategies discussed by Dietz and Robinson (May 19 issue).1 Even the most powerful behavioral methods to promote weight loss in obese children are not likely to succeed if they promote inefficacious dietary prescriptions.

Low-fat diets do not result in more weight loss than higher-fat diets, according to a recent meta-analysis.2 Low-carbohydrate diets lead to short-term but not long-term weight loss, and their safety in children has not been evaluated.

An alternative approach focuses on the glycemic index, rather than the restriction of any macronutrient. Highlights of over 100 studies indicate that children eat less after meals with a low glycemic index than after those with a high glycemic index3; the glycemic index is directly associated with body weight in observational analyses4; adolescents and adults lost more weight on diets that had a low glycemic index than on control diets in randomized, controlled trials lasting up to one year; and rodents fed a low-glycemic-index diet had 40 to 50 percent less body fat than rodents fed a high-glycemic-index diet.5

David S. Ludwig, M.D., Ph.D.
Cara B. Ebbeling, Ph.D.
Children's Hospital Boston, Boston, MA 02115
david.ludwig@childrens.harvard.edu

5 References

1. 1

   Dietz WH, Robinson TN. Overweight children and adolescents. N Engl J Med 2005;352:2100-2109
   Full Text | Web of Science | Medline

2. 2

   Pirozzo S, Summerbell C, Cameron C, Glasziou P. Should we recommend low-fat diets for obesity? Obes Rev 2003;4:83-90[Erratum, Obes Rev 2003;4:185.]
   CrossRef | Medline

3. 3

   Ludwig DS. The glycemic index: physiological mechanisms relating to obesity, diabetes, and cardiovascular disease. JAMA 2002;287:2414-2423
   CrossRef | Web of Science | Medline

4. 4

   Ma Y, Olendzki B, Chiriboga D, et al. Association between dietary carbohydrates and body weight. Am J Epidemiol 2005;161:359-367
   CrossRef | Web of Science | Medline

5. 5

   Pawlak DB, Kushner JA, Ludwig DS. Effects of dietary glycaemic index on adiposity, glucose homeostasis, and plasma lipids in animals. Lancet 2004;364:778-785
   CrossRef | Web of Science | Medline

To the Editor:

Dietz and Robinson state that “other strategies that appear promising but have not been tested in randomized trials include the reduced consumption of sugar-sweetened beverages.” We showed in a randomized trial that a school-based education program that is focused on delivering the message “ditch the fizz” to reduce consumption of sodas and other fizzy drinks can be successful (clinically and statistically) in preventing a rise in the number of overweight and obese children 7 to 11 years old.1 Such strategies warrant broader implementation.

David Kerr, M.D.
Bournemouth Diabetes and Endocrine Centre, Bournemouth BH7 7DW, United Kingdom

1 References

1. 1

   James J, Thomas P, Cavan D, Kerr D. Preventing an increase in childhood obesity by reducing consumption of carbonated soda: cluster randomised controlled trial. BMJ 2004;328:1237-1237
   CrossRef | Web of Science | Medline

Author/Editor Response

We agree that more data are critically needed regarding the safety, efficacy, and effectiveness of all dietary therapies in children and adolescents, including diets that have a low glycemic index, as noted by Ludwig and Ebbeling. However, behavioral, social, and environmental issues that promote adherence will probably be at least as important if not more important than the characteristics of the diet. In practice, implementation of dietary prescriptions is probably affected by many mediating and moderating factors, such as physical activity, sedentary behavior patterns, and biologic characteristics, and weight changes will result from the total effect on net energy balance.

Kerr calls our attention to a school-based intervention aimed at the reduction of soft-drink intake,1 and he suggests that such strategies warrant broader implementation. As we pointed out in our article, school-based interventions that include reduced television viewing have reduced rates of weight gain and other measures of adiposity in elementary school students2 and, in combination with increased physical activity, increased fruit and vegetable intake, and a low-fat diet, reduced the prevalence of obesity in middle-school girls.3 In the article cited by Kerr, a five-session classroom program to reduce the intake of soft drinks was associated with significant 12-month changes in the prevalence among children of a body mass index above the 91st percentile.1 This study is a welcome addition to the literature that should be followed with additional research. However, as noted by others,4 a number of key methodologic limitations prevent more definitive interpretation of the validity and generalizability of the intervention cited by Kerr. As we indicated, reduced consumption of sugar-sweetened beverages is a promising weight-control strategy. There is a critical need to determine the effect on weight of strategies aimed at changing choices of beverages available to children in schools, and the effect of the behavioral changes that reduce the consumption of sugar-sweetened drinks at home.

William H. Dietz, M.D., Ph.D.
Centers for Disease Control and Prevention, Atlanta, GA 30341

Thomas N. Robinson, M.D., M.P.H.
Stanford University School of Medicine, Stanford, CA 94305

4 References

1. 1

   James J, Thomas P, Cavan D, Kerr D. Preventing an increase in childhood obesity by reducing consumption of carbonated soda: cluster randomised controlled trial. BMJ 2004;328:1237-1237
   CrossRef | Web of Science | Medline

2. 2

   Robinson TN. Reducing children's television viewing to prevent obesity: a randomized controlled trial. JAMA 1999;282:1561-1567
   CrossRef | Web of Science | Medline

3. 3

   Gortmaker SL, Peterson K, Wiecha J, et al. Reducing obesity via a school-based interdisciplinary intervention among youth: Planet Health. Arch Pediatr Adolesc Med 1999;153:409-418
   Web of Science | Medline

4. 4

   French SA, Hannan PJ, Story M. School soft drink intervention study. BMJ 2004;329:E315-E316
   CrossRef | Medline

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1. 1

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2. 2

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