Effects of a low glycemic load or a low-fat dietary intervention on body weight in obese Hispanic American children and adolescents: a randomized controlled trial

Abstract

Background: In Hispanic children and adolescents, the prevalence of obesity and insulin resistance is considerably greater than in non-Hispanic white children. A low-glycemic load diet (LGD) has been proposed as an effective dietary intervention for pediatric obesity, but to our knowledge, no published study has examined the effects of an LGD in obese Hispanic children.

Objective: We compared the effects of an LGD and a low-fat diet (LFD) on body composition and components of metabolic syndrome in obese Hispanic youth.

Design: Obese Hispanic children (7-15 y of age) were randomly assigned to consume an LGD or an LFD in a 2-y intervention program. Body composition and laboratory assessments were obtained at baseline and 3, 12, and 24 mo after intervention.

Results: In 113 children who were randomly assigned, 79% of both groups completed 3 mo of treatment; 58% of LGD and 55% of LFD subjects attended 24-mo follow-up. Compared with the LFD, the LGD decreased the glycemic load per kilocalories of reported food intakes in participants at 3 mo (P = 0.02). Both groups had a decreased BMI z score (P < 0.003), which was expressed as a standard z score relative to CDC age- and sex-specific norms, and improved waist circumference and systolic blood pressure (P < 0.05) at 3, 12, and 24 mo after intervention. However, there were no significant differences between groups for changes in BMI, insulin resistance, or components of metabolic syndrome (all P > 0.5).

Conclusions: We showed no evidence that an LGD and an LFD differ in efficacy for the reduction of BMI or aspects of metabolic syndrome in obese Hispanic youth. Both diets decreased the BMI z score when prescribed in the context of a culturally adapted, comprehensive weight-reduction program.

Trial registration: ClinicalTrials.gov NCT01068197.

Figures

FIGURE 1.

Flow of participants throughout the study. GCRC, General Clinical Research Center.

FIGURE 2.

Effect of the intervention on BMI. Means (± SDs) for imputed BMI (A) and completers BMI (B) for the entire study period for the LGD (closed circles) and LFD (open circles). Effects of group assessed by using mixed-effects multiple linear regression for the entire 2-y study period were as follows: for imputed analysis, P = 0.59; for completer analysis, P = 0.44. For imputed analysis, n = 57 in the LGD and n = 56 in the LFD. For completer analysis, n = 57 (baseline), n = 45 (3 mo), n = 36 (12 mo), and n = 33 (24 mo) in the LGD; n = 56 (baseline), n = 44 (3 mo), n = 33 (12 mo), and n = 31 (24 mo) in the LFD. LFD, low-fat dietary group; LGD, low–glycemic load dietary group.