The blueprint toolkit is the result of 18 months of evidence synthesis, quantitative analysis and consultation with academic experts in the field of obesity, health and the food system.
The project consisted of eight core components, which are outlined on this page. For full details of the methodology please see the technical appendix.
We reviewed reports published over the past five years that have proposed policies to tackle obesity. This resulted in a list of over 150 recommendations. To create a user-friendly list for policymakers, we selected over 30 policies that were most frequently featured at the forefront of the debate, prioritising those with the greatest potential to improve health. To our knowledge, this project is the most scientifically robust attempt at comparing the impact of multiple policies.
We conducted 30 rapid reviews to identify a per-person effect size that would be achieved if the policy were implemented. Our search strategy and systematic methods ensured the selection of the highest quality evidence and we tested our findings with our Expert Advisory Group.
For each policy we built an analytical model in order to transform the effect size identified in literature reviews (eg, change in weight, physical activity or daily calorie intake) into our metric of interest: reduction in national obesity prevalence.
First, if there was evidence that a policy reduced calorie intake during a single eating occasion, we applied a standardised ‘compensation effect’ to ensure we were not overestimating the effects of the policy on net daily calorie intake.
Next, we used a modelling technique developed by Hall et al. (2011) to estimate the impact of each policy on per-person weight change. This model is considered the gold standard methodology and was the basis of the Department of Health and Social Care’s calorie model.
Next, the body weight change was applied to body weight data reported in the Health Survey for England (HSE, 2019) and Scottish Health Survey to generate a population BMI distribution if the policy were implemented. Next, we added population reach assumptions to each policy model. The toolkit compares both treatment (lower reach) and prevention (higher reach) policies. For treatment policies, we estimated the total number of people exposed to the policy and added this assumption to the model.
Between January 2023 and June 2024, we held four workshops with our Expert Advisory Group to test our methodology in modelling the impact of each policy on national obesity rates. Our quantitative analysis provided a percentage reduction score and enabled us to rank each policy by magnitude of impact. We tested this ranking by sharing a survey with over 100 academic experts, inviting them to provide feedback on our findings. Forty-two experts completed the survey. Analysis of this survey, in addition to final consultation with our Expert Advisory Group, did not result in suggestions for correcting for any specific effect sizes.
Obesity rates are highest in the most deprived communities and so the impact of policies on different communities was important to consider. For each policy, we scoped the potential effects on health inequalities. We primarily did this by considering the level of agency each policy requires from individuals. Policies that require individuals to use a high level of agency (including for example, motivation, resources, knowledge) to benefit were considered as potentially exacerbating health inequalities. In contrast, those that require less agency from individuals to benefit were considered most equitable. Where possible, we incorporate findings from studies that evaluate the differential effect of policies on different groups. We encourage readers to reach out to ahealthylife@nesta.org.uk if there is further data information that should be included.
We commissioned HealthLumen, specialists in modelling the future economic burden of disease, to calculate the costs of each policy. The cost scores are based on literature reviews to identify costs associated with delivering each policy, and where said costs are incurred (eg, governments, industry). Costs found in the literature spanned the years 1999-2024, and were scaled to match current rates of inflation using the Campbell and Cochrane Economics Methods Group (CCEMG) and Evidence for Policy and Practice Information (EPPI) Cost Converter. For further details on methodology of converting costs, please see our technical appendix. We estimated the costs to the government at a UK level and assume that costs to devolved governments are a standardised proportion of the total.
The cost indicator of ‘high’, ‘medium’ and ‘low’ assigned to each policy within the toolkit is based on the total cost to the government over a five-year period. We present a breakdown of these costs in the detail of each policy page.
Please see the reports and the appendices below.
HealthLumen calculated the impact of each policy on the cumulative incidence of 10 diseases over a five-year period. Selected diseases included in the analysis were type 2 diabetes, hypertension, coronary heart disease, colorectal cancer, gallbladder disease, ovarian cancer, stroke, liver cancer, depression, and selected musculoskeletal diseases. Diseases were selected based on the strength of evidence of an association between having obesity and the risk of having (or developing) the disease. There is growing evidence of an association between obesity and risk of developing a wider range of diseases, however we included diseases with the strongest evidence base to ensure conservative estimates.
We developed a novel scale informed by guidance published by the Department for International Development for assessing evidence. We asked our Expert Advisory Group to rate the strength of evidence for each policy, taking account of both reliability (the size and consistency), as well as the validity (the quality and applicability) of the evidence base.
The cost indicator of ‘high’, ‘medium’ and ‘low’ assigned to each policy within the toolkit is based on the total cost to the government over a five-year period. We present a breakdown of these costs in the detail of each policy page.
For each policy we estimated the annual cost saving to the UK and devolved governments using analysis conducted by Frontier Economics for The Tony Blair Institute (2023). This analysis showed that current rates of obesity incur an annual cost of £74 billion (this excludes the costs attributed to rates of overweight). These costs are broken down into quality adjusted life years (QALYs), social care costs (both formal and informal), NHS costs, and productivity losses (primarily driven by losses driven by economic inactivity and early exit from the labour market).
| Obesity | Overweight | Total | |
| Individual costs | 53.6 | 9.5 | 63.1 |
| Quality-adjusted life years | 48.1 | 8.5 | 56.6 |
| Informal social care | 5.5 | 1.0 | 6.5 |
| NHS costs | 11.4 | 7.9 | 19.2 |
| Obesity-related illnesses | 11.3 | 7.9 | 19.2 |
| Mental health | 0.0 | 0.0 | 0.0 |
| Wider costs | 9.3 | 6.2 | 15.1 |
| Productivity losses | 8.9 | 6.2 | 15.1 |
| Formal social care | 0.4 | 0.1 | 0.5 |
| Total costs | 74.3 | 23.6 | 97.9 |
We used this data to estimate the potential cost saving to the UK and devolved governments if a given policy were implemented. Given that future trajectories of national obesity rates (plus inflation) predict an increase in government spending over the next 10 years, it is important to note that savings reported in our toolkit reflect preventing additional spending rather than an absolute reduction in spending.