The effect of regular increased physical activity, and regular consumption of ready-to-eat-cereal (RTEC) breakfasts and afternoon snacks on the weight of young adolescents attending public Gauteng schools
Thesis (MNutr (Human Nutrition))--Stellenbosch University, 2008.
Obesity is recognizably a chronic disease worldwide and childhood obesity has considerable implications for long‐term health. Manipulation of modifiable lifestyle variables, such as high‐fat energy‐dense diets and decreased physical activity are often recommended for positive (although not always significant) outcomes. This study aimed to determine the specific relationships between ready‐to‐eat cereals (RTEC) consumption (regular RTEC breakfast consumption and regular RTEC afternoon snack consumption), regular increased physical activity, and anthropometric measures [body weight, percentage body fat, and body mass index (BMI)] amongst young adolescents attending public Gauteng schools. A randomised controlled trial was conducted over 5‐weeks amongst 212 cross‐cultural, male and female, English speaking children aged 10‐13 years attending two selected public Gauteng schools. Participants were randomly allocated to one of four cohorts (Control, Step, RTEC or Step & RTEC). The control cohort had no prescribed intervention, the Step cohort had prescribed stepping intervention only (completion of 2 000 additional steps in a 20‐minute period on 3 school days per week), the RTEC cohort had prescribed RTEC consumption intervention only (consumption of a single RTEC serving at breakfast and RTEC snack serving as an afternoon snack on each school day), and the Step & RTEC cohort had both the prescribed stepping and RTEC consumption interventions. Participants were assessed anthropometrically at baseline and at the end of the 5 weeks. They also submitted a food/activity diary from which quantitative measures of their intake and activity were determined. The Step (107 845 ± 31 251) and Step & RTEC (108 793 ± 26 285) cohorts both completed significantly more mean total steps than Control (83 501 ± 22 302) and RTEC (86 082 ± 23 367) cohorts (p≤0.01), and a significant negative correlation (p=0.02; r=‐0.21) was found between the change in percentage body fat and the total steps completed. The Step & RTEC (14.32 ± 7.95) and RTEC (16.06 ± 8.82) cohorts consumed more RTEC snack servings as afternoon snacks than Control (1.13 ± 1.69) and Step (1.59 ± 2.50) cohorts (p≤0.01), and a significant negative correlation (p=0.03; r=‐0.20) was found between the participants’ change in weight and the servings of RTEC snacks consumed as an afternoon snack. No significant difference (p=0.35) was achieved in mean weight change across the four cohorts, although both Step & RTEC (‐0.12 ± 0.81) and RTEC (‐0.24 ± 0.77) cohorts showed a mean decrease in body weight. No significant difference (p=0.47) was achieved in mean change in percentage body fat across the four cohorts either, although all cohorts showed a decrease in percentage body fat, with Step cohort (‐0.32 ± 0.70) showing the greatest mean change. The stepping intervention alone brought about greatest decrease in percentage body fat, while the RTEC consumption intervention alone brought about greatest decrease in body weight and BMI. The combination of interventions was the least effective of the three interventions in bringing about decreases in percentage body fat.