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Randomised controlled trial
Six-month interventions – parent-centred dietary modification alone or in combination with child-centred physical activity may reduce child BMI at 2 years
  1. Anthea Magarey
  1. Flinders University, Adelaide, South Australia, Australia
  1. Correspondence to Anthea Magarey
    Nutrition and Dietetics, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia; anthea.magarey{at}

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The need for interventions to manage the global epidemic of childhood overweight is well recognised,1 and, increasingly, the role of parents in this process is acknowledged for early school-aged children.2 However, the evidence to guide such interventions is limited. Many studies have methodological limitations and short follow-up periods.1 Most interventions in adult and child populations show positive outcomes at the end of the intervention period, but it is the sustainability of these that is of paramount interest.

The study by Collins and colleagues addresses many of the limitations of previous studies, reports sustainability of the intervention 2 years from baseline and provides further evidence of the key role of parents.


The Hunter Illawarra Kids Challenge Using Parent Support study was a randomised controlled trial that compared three 6-month treatment arms, a parent-centred dietary modification programme (Diet), a child-centred physical activity programme (Activity) and the two programmes combined (Diet+Activity). Two hundred and six overweight children were randomised with 165 completing baseline assessments. This study reports the 24-month outcomes using an intention to treat analysis with 22 (50%), 35 (56%) and 36 (60%) from the Diet, Activity and combined arms, respectively, assessed. Primary outcomes were body mass index (BMI) z-score and waist circumference. Secondary outcomes were a range of metabolic variables and behaviour outcomes of energy intake and physical activity.


At 24 months, BMI z-score was significantly lower than at baseline in all three groups, and there was a weak (p=0.04) significant group by time difference with greater decreases in the Diet and Diet+Activity groups than in the Activity group, and the greatest difference between the Diet and Activity groups. There were no other significant group by time effects, but there were significant time effects in all groups for waist circumference, a number of the metabolic outcomes and energy intake but not for physical activity.


This study adds to the evidence base for interventions to manage overweight children up to 10 years of age. The previously reported results3 of a significant relative weight loss at 12 months in each arm was sustained to 24 months. The group difference of greater change in the arms that included a parent-centred diet programme, at 12 months, was maintained, but the hypothesis of greater effect of the Diet+Activity arm compared with each of the programmes alone was rejected. Although an intention to treat analysis was conducted on the impact of the 50–60% retention of those on whom baseline data were available (approximately 45% of those allocated), the results were not clear. The authors state there were no significant differences between those who were followed up and those who were not (variables not stated) and also state that those who were not followed up at 24 months had higher baseline BMI z-scores. An exploration of this finding would have enhanced the interpretation of the outcomes of this study.4 In any case, the results were difficult to interpret given only 45% of those allocated were analysed.

The findings of the greater effectiveness of the arms that included a parent-centred diet programme suggest that targeting parents may be more effective, but it is difficult to distinguish the impact of parents from the impact of the diet intervention. However, in support of the importance of engaging parents, the strong evidence is for the impact of parenting style on eating and parents' role in determining the eating environment for children of this age.2 Of interest would be whether parenting skills were enhanced as a result of participation in this programme. Another recent Australian study which targeted parents as the agents-of-change, as proposed in the original work in this area by Golan et al,5 reported improved parenting outcomes at the end of a 6-month programme and these were sustained to 24 months as were the improvements in relative weight loss.6 Finally, as the evidence mounts as to efficacy of interventions, there is increasing need to determine whether these can be translated from the research setting to community-based practice.


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  • Competing interests None.

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