Role of carbohydrate modification in weight management among obese children: a randomized clinical trial

Abstract

Objective: To compare the effectiveness and safety of carbohydrate (CHO)-modified diets with a standard portion-controlled (PC) diet in obese children.

Study design: Obese children (n=102) aged 7-12 years were randomly assigned to a 3-month intervention of a low-CHO (LC), reduced glycemic load (RGL), or standard PC diet, along with weekly dietary counseling and biweekly group exercise. Anthropometry, dietary adherence, and clinical measures were evaluated at baseline and 3, 6, and 12 months. Analyses applied intention-to-treat longitudinal mixed models.

Results: Eighty-five children (83%) completed the 12-month assessment. Daily caloric intake decreased from baseline to all time points for all diet groups (P<.0001), although LC diet adherence was persistently lower (P<.0002). At 3 months, body mass index z score was lower in all diet groups (LC, -0.27 ± 0.04; RGL, -0.20 ± 0.04; PC, -0.21 ± 0.04; P<.0001) and was maintained at 6 months, with similar results for waist circumference and percent body fat. At 12 months, participants in all diet groups had lower body mass index z scores than at baseline (LC, -0.21 ± 0.04; RGL, -0.28 ± 0.04; PC, -0.31 ± 0.04; P<.0001), and lower percent body fat, but no reductions in waist circumference were maintained. All diets demonstrated some improved clinical measures.

Conclusion: Diets with modified CHO intake were as effective as a PC diet for weight management in obese children. However, the lower adherence to the LC diet suggests that this regimen is more difficult for children to follow, particularly in the long term.

Figure 1

Flow Diagram of Participants through the Trial

Figure 2

Anthropometric Outcomes and Dietary Adherence by Diet Group. Least square means ± SE presented from repeated measures mixed models for A, BMI Z-score, B, waist circumference and C, % body fat. Significant differences (p ≤ 0.0024) within each diet group versus baseline: ^a LC; ^b RGL; ^c PC. D, Percent of participants within each diet group adhering to dietary recommendations. Significant differences (p ≤ 0.0024) from baseline (^a, ^b, and ^c designations as in 2A-2C) and pairwise differences among diet groups indicated as follows: ^d LC vs. RGL; ^e LC vs. PC using Fisher Exact Test.

Figure 3

Dietary Intake by Diet Group. Least square means ± SE presented from repeated measures mixed models for A, total caloric intake, B, carbohydrate (g/day), C, carbohydrate (% of kcal), D, glycemic load, E, protein and F, fat. Significant differences (p ≤ 0.0024) between diet groups indicated as follows: ^d LC vs. RGL; ^e LC vs. PC; ^f RGL vs. PC.