A randomized controlled trial to investigate the impact of a low glycemic index (GI) diet on body mass index in obese adolescents

Alice Ps Kong,Albert M Li,Chung Shun Ho,Ruth Sm Chan,C Jeyakumar Henry,Juliana Cn Chan,Risa Ozaki,Kai Chow Choi,Mandy Sea,Michael Hm Chan,Kris Lok,Jean Woo

doi:10.1186/1471-2458-14-180

Alice Ps Kong, Albert M Li + Show 10 more

Open Access

https://doi.org/10.1186/1471-2458-14-180

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Abstract

BackgroundThe role of a low glycemic index (GI) diet in the management of adolescent obesity remains controversial. In this study, we aim to evaluate the impact of low GI diet versus a conventional Chinese diet on the body mass index (BMI) and other obesity indices of obese adolescents.MethodsObese adolescents aged 15–18 years were identified from population-recruited, territory-wide surveys. Obesity was defined as BMI ≥95th percentile of Hong Kong local age- and sex-specific references. Eligible subjects were randomized to either an intervention with low GI diet (consisting of 45-50% carbohydrate, 30-35% fat and 15-20% protein) or conventional Chinese diet as control (consisting of 55-60% carbohydrate, 25-30% fat and 10-15% protein). We used random intercept mixed effects model to compare the differential changes across the time points from baseline to month 6 between the 2 groups.Results104 obese adolescents were recruited (52 in low GI group and 52 in control group; 43.3% boys). Mean age was 16.7 ± 1.0 years and 16.8 ±1.0 years in low GI and control group respectively. 58.7% subjects completed the study at 6 months (65.4% in low GI group and 51.9% in control group). After adjustment for age and sex, subjects in the low GI group had a significantly greater reduction in obesity indices including BMI, body weight and waist circumference (WC) compared to subjects in the control group (all p <0.05). After further adjustment for physical activity levels, WC was found to be significantly lower in the low GI group compared to the conventional group (p = 0.018).ConclusionLow GI diet in the context of a comprehensive lifestyle modification program may be an alternative to conventional diet in the management of obese adolescents.Trial registration numberClinicalTrials.gov Ref. No: NCT01278563

Highlights

The role of a low glycemic index (GI) diet in the management of adolescent obesity remains controversial
104 obese adolescents were recruited in this study (52 in the low GI group and 52 in the control group; 43.3% boys; mean age 16.8 ± 1.0 years; mean body mass index (BMI) 30.9 ± 3.9 kg/m2)
Obesity indices between adolescents in the control and low GI groups were similar except adolescents in control group were less centrally obese and tended to have lower body fat compared to the low GI group [waist circumference and body fat percentage of the control and low GI group were 92.3 ± 9.8 and 96.5 ± 10.9 cm (p = 0.043), and 36.8 ± 8.3 and 39.8 ± 10.9% (p = 0.051) respectively]

Summary

Introduction

The role of a low glycemic index (GI) diet in the management of adolescent obesity remains controversial. We aim to evaluate the impact of low GI diet versus a conventional Chinese diet on the body mass index (BMI) and other obesity indices of obese adolescents. Obesity is a prevalent condition in both the adult and in the adolescent population. Emerging evidence suggests that low GI diet may be more efficacious than an energy-restricted, low fat diet in reducing body weight [12,13,14]. Against this background, we conducted this randomized controlled trial aiming to study the changes in obesity indices in obese adolescents randomized to low GI diet versus a conventional Chinese diet as control

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