Executive summary
Overweight, which includes obesity, affects over half of all men and women living in OECD countries. While the causes underpinning the rise in overweight are multifaceted and complex, changes in lifestyles including unhealthy diets and insufficient physical activity are the two leading risk factors.
People living with overweight are at greater risk of developing non-communicable diseases (NCDs) such as type 2 diabetes, cancers and cardiovascular diseases. Frequent use of health care services and higher health care costs are associated with such diseases. Overweight also has an indirect negative economic impact by depressing workforce productivity, for example through higher rates of absenteeism.
Over 90% of OECD countries have action plans for unhealthy diets and physical inactivity. Interventions included in these action plans typically influence people to make healthier choices (e.g. food labelling), widen the availability of healthy choices (e.g. green spaces), change the price of goods (e.g. tax on sugary drinks) or restrict access to unhealthy products (e.g. banning unhealthy foods in certain spaces).
Twelve interventions including food-labelling schemes, lifestyle counselling programmes, community- and school-based programmes, as well as mHealth apps were selected for analysis. Interventions were selected based on submissions by countries and do not aim to be comprehensive. Rather, they represent those that are of key strategic interest, therefore, other countries are considering similar approaches.
Each intervention was examined against a common set of frameworks – specifically, an assessment of the intervention against several best practice criteria including effectiveness, efficiency and equity, and second, an assessment to determine the transferability of the intervention.
The use of validated assessment frameworks and a focus on the economic impact of interventions provides policy makers with a unique, in-depth analysis of interventions tackling overweight. The analysis also fills a knowledge gap regarding the potential to transfer interventions to other regions.
An analysis of selected interventions using the OECD microsimulation model – Strategic Planning for Public Health NCD model – shows their potential to reduce disease incidence, in particular, musculoskeletal disorders and cardiovascular diseases.
Results from modelling exercises also reveal that the selected interventions are efficient as they reduce health expenditure and improve workforce productivity. As a result, many interventions are not only cost effective, but also cost saving. For example, Nutri-Score, a front-of-pack health food label first introduced in France, is expected to be cost saving if scaled-up and transferred to all OECD and EU27 countries.
Create comprehensive policy packages. Among the selected interventions, changes in diet and physical activity outcomes were sometimes small, not statistically significant and limited in scope when assessed from a population-wide perspective. This is not surprising given the causes of overweight are complex and multifaceted meaning there is no “silver bullet” solution. For this reason, policy makers should focus on comprehensive policy packages that include several complementary interventions. Namely, “downstream” interventions focused on changing people’s behaviour as well as “upstream” interventions that change the environment in which people live, such as food reformulation, food procurement, and more green spaces.
Target the needs of disadvantaged groups. Overweight disproportionately affects people with a lower socio-economic status. Despite this, the selected interventions infrequently targeted or reported health outcomes for disadvantaged groups. Further, among interventions that did, the results were mixed, highlighting the difficulty of reducing health inequalities. Further efforts are necessary to address the needs of disadvantaged groups. Key policy actions include boosting levels of health literacy (HL), given HL is typically lower in disadvantaged groups, adapting programmes to the specific needs of certain groups (such as offering services in other languages), and utilising diverse communication and recruitment strategies to increase uptake among underrepresented groups.
Boost participation in weight reduction programmes. Changing people’s behaviour is complex; particularly in relation to behaviours that affect rates of overweight given they are shaped by cultural, socio-economic and environmental factors. Therefore, it is not surprising that weight loss interventions analysed as part of this report suffered from recruitment and retention issues. Policy makers can improve uptake and retention using several strategies such as providing social support and asking participants to set goals targeting behaviour change. Such strategies will increase the likelihood of the intervention being effective in the long term.
Adequately resource transfer and scale-up efforts. Over half of all selected interventions were transferred from their original country (i.e. the owner) to another country (i.e. the target). An analysis of the transfer process revealed successful transfers are complex and require a thorough understanding of both the owner and target setting. To assist the spread of best practice interventions, policy makers should dedicate resources to support the transfer or scale-up process. Additional resources can be spent on building close ties between key personnel in the owner and target country (e.g. through regular in-person meetings), developing practical implementation guides, as well as further research to understand differences between the owner and target country and how this may affect the transfer process.
Provide incentives that strengthen evidence-based research. Randomised controlled trials (RCTs) are the “gold standard” in establishing causal effects given their potential to reduce bias. Among selected interventions, nearly half were evaluated using an RCT with the remainder relying on observational study designs, which are practical and often desirable in public health. To enhance the quality of evidence supporting overweight interventions, policy makers can set minimum evidence-based standards when determining which interventions to scale-up or transfer; require researchers to submit an evaluation study design when applying for funding; promote collaborative research between academics and public health bodies; and dedicate a proportion of funds to monitoring and evaluation.