Part 3: Methodology
Strand 4: Evidence for a Whole Systems Approach to Obesity
Video
Learning Objectives
After watching this section, you should be able to:
- Describe the methodology used to conduct the rapid evidence synthesis on whole systems approaches to obesity
- Summarise the key findings from each of the five systematic reviews included in the synthesis
- Identify what the evidence suggests about the conditions most likely to support effective whole systems approaches to obesity
Key Points
- The synthesis was structured around two main sections: key review studies (peer-reviewed evidence) and national/international case studies; the MINER framework was applied to assess case study quality
- Bagnall (2019): 65 studies showed improvements in BMI, parental and community awareness, capacity building, nutrition, physical activity, environment changes, and community well-being
- Baker: 25 studies on community-wide physical activity interventions found limited evidence; better-designed studies were needed
- Bleach et al. (2013): 9 studies of community-based childhood obesity prevention found that the presence of a policy change was most likely to produce the greatest effect; some encouraging BMI improvements were found at one-year follow-up
- Safford: 14 international WSA approaches to childhood obesity; only 3 of 14 reported positive outcomes in healthy behaviours and anthropometric measures (e.g., Healthy Live Cambridge Kids, Romp and Chomp, Shape Up Somerville)
- Skinner and Foster: 21 studies; argued that systems science methods (causal loop diagrams, agent-based models) should be built into WSA to obesity and require interdisciplinary teams spanning psychosocial, clinical, public health, and systems science expertise
Further Reading
- Bagnall AM et al. (2019). Whole systems approaches to obesity and other complex public health challenges: a systematic review. BMC Public Health, 19, 8. — the first and most substantial of the five systematic reviews summarised in this video; open access
- Bleich SN et al. (2013). Systematic review of community-based childhood obesity prevention studies. Pediatrics, 132(1), e201–e210. — the review that identified policy change as the factor most likely to produce the greatest effect on childhood obesity prevention outcomes
- A whole systems approach to obesity prevention: a rapid synthesis of evidence — the IPH report for Northern Ireland that synthesised these five reviews alongside the international case studies (Breslin et al., 2023)
- Baker PRA et al. (2015). Community wide interventions for increasing physical activity. Cochrane Database of Systematic Reviews. — the Baker review of 25 studies on community-wide, multi-strategic physical activity interventions; found limited evidence and called for better-designed studies
- Skinner AC & Foster EM (2013). Systems science and childhood obesity: a systematic review and new directions. Journal of Obesity. — argues that systems science methods (causal loop diagrams, agent-based models) should be built into WSA to obesity; requires interdisciplinary teams
Knowledge Check
Complete the questions below before moving on.
According to the Bleach et al. (2013) systematic review of community-based childhood obesity prevention studies, which factor was most likely to produce the biggest effect on obesity prevention?
The correct answer is the presence of a policy change within the community-based intervention. The Bleach et al. (2013) review found nine studies of community-based childhood obesity prevention, and concluded that where a policy change was part of the intervention, this was most likely to have the biggest effect on obesity or overweight outcomes. This underlines the importance of embedding whole systems approaches within wider policy frameworks rather than relying on programme delivery alone.
- False — BMI z-scores were used as an outcome measure in several studies, but this is a measurement choice, not an intervention factor linked to effect size.
- True
- False — although five studies used randomised controlled trials, the review highlighted policy change, not study design, as the key factor driving effect.
- False — while three studies were conducted in community and school settings combined, the review did not identify school-only delivery as the strongest factor; the presence of policy change was.