The participants were randomly selected and assigned to
two groups. The groups comprised 30 obese adolescents
aged from 11–15 years who participated in a 6-month
intervention program. The sample size calculation for this
study was based on previously reported intervention
changes in weight and body mass index (BMI) in children.
These suggested that at least 14 in each group would allow
detection of statistically significant differences with an
effect size of 0Æ80 (Breat et al. 2004). The participants
had BMI greater than the 95th percentile related to
standards for age and gender (Wong & Whaley 2007).
The exclusion criteria were pre-existing disease or an
organic cause for obesity and receiving any medication that
might interfere with the study. All participants were
examined by a Registered Paediatric Nurse to exclude
these factors.