What change in body mass index is associated with improvement in percentage body fat in childhood obesity? A meta-regression

Laura Birch*, Rachel Perry, Linda P. Hunt, Rhys Matson, Amanda Chong, Rhona Beynon, Julian P.H. Shield

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

22 Citations (Scopus)
177 Downloads (Pure)


OBJECTIVE: Using meta-regression this paper sets out the minimum change in body mass index-SD score (BMI-SDS) required to improve adiposity as percentage body fat for children and adolescents with obesity.

DESIGN: Meta-regression.

SETTING: Studies were identified as part of a large-scale systematic review of the following electronic databases: AMED, Embase, MEDLINE via OVID, Web of Science and CENTRAL via Cochrane library.

PARTICIPANTS: Individuals aged 4-19 years with a diagnosis of obesity according to defined BMI thresholds.

INTERVENTIONS: Studies of lifestyle treatment interventions that included dietary, physical activity and/or behavioural components with the objective of reducing obesity were included. Interventions of <2 weeks duration and those that involved surgical and/or pharmacological components (eg, bariatric surgery, drug therapy) were excluded.

PRIMARY AND SECONDARY OUTCOME MEASURES: To be included in the review, studies had to report baseline and post-intervention BMI-SDS or change measurements (primary outcome measures) plus one or more of the following markers of metabolic health (secondary outcome measures): adiposity measures other than BMI; blood pressure; glucose; inflammation; insulin sensitivity/resistance; lipid profile; liver function. This paper focuses on adiposity measures only. Further papers in this series will report on other outcome measures.

RESULTS: This paper explores the potential impact of BMI-SDS reduction in terms of change in percentage body fat. Thirty-nine studies reporting change in mean percentage body fat were analysed. Meta-regression demonstrated that reduction of at least 0.6 in mean BMI-SDS ensured a mean reduction of percentage body fat mass, in the sense that the associated 95% prediction interval for change in mean percentage body fat was wholly negative.

CONCLUSIONS: Interventions demonstrating reductions of 0.6 BMI-SDS might be termed successful in reducing adiposity, a key purpose of weight management interventions.


Original languageEnglish
Article numbere028231
Number of pages16
JournalBMJ Open
Publication statusPublished - 30 Aug 2019


  • adolescence
  • body fat
  • body mass index
  • childhood
  • obesity

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