Enforce front-of-pack labelling 

We estimated that this policy would reduce the prevalence of adult UK obesity rates 3%

Estimating the per-person impact

We estimated that this policy would reduce average daily calorie intake by approximately 7.4 kcal per person

The intervention modelled interpretative FOPL but does not include warning labels. We did not purposefully exclude warning labels, but rather used the best available literature for interpretative FOPL, which happened not to include them.

In the Cochrane Review conducted by Clarke et al. (2025), two types of FOPL were used for meta-analysis: Nutri Repère and Nutri Couleurs. These were selected as they met the intervention criteria of being forms of calorie/energy labelling. See example images of the labels below, reproduced from Dubois et al. (2021).

We estimated the impact on daily calorie reduction using the Cochrane review Clarke et al. (2025). We extracted the meta-analysis results from the most appropriate subset of studies included in this review (ie, those with the highest potential for real-world generalisability, focused on stores as a setting, ie, where food would be pre-packaged). Specifically, we used the meta-analysis in Analysis 1.2 (pg. 89), Comparison 1.2.2 (‘Stores’), with results based on two eligible comparisons of Dubois et al. (2021).

This study found that labels were effective in reducing the purchase of calories by 0.05 SMD in comparison to no labels. This is equivalent to a 0-54 kcal reduction in energy intake per person per day as published in Hollands et al. (2015).  For the modelling, we assume an average reduction of 27 calories per person (adult) per day.

A series of methodological adjustments were applied to refine this estimate. First, our analysis corrected for underreporting in the National Diet and Nutrition Survey by applying a 1.32 multiplier. This is based on a 32% underestimation of calorie intake reported in a doubly labelled water study on NDNS data conducted by ONS. This resulted in increasing the effect to 35.6 kcals. The estimate was then adjusted to exclude out-of-home consumption (estimated to contribute 11% to our daily calories on average) and non-packaged food (estimated to account for, on average, 7% of calories from retailers). To reflect real-world implementation, the effect size was further adjusted for the current baseline FOPL coverage of 66% by multiplying by 0.34, yielding 10.01 kcals, and finally incorporated a 23% compensation effect. This systematic adjustment process resulted in a final input of -7.4 kcals per person per day, representing our estimate of FOPL’s potential impact on daily energy intake.

The impact of product reformulation was not included in the modelling due to a lack of quantitative evidence on this. However, we do anticipate that reformulation is a possible mechanism for calorie change following mandatory FOPL. Some manufacturers are likely to reformulate their products in order to improve their labels, which could have a further impact on obesity. This is corroborated by evidence from Chile –  mandatory warning labels were implemented there in 2016, leading to ~15% of “high in” products being reformulated according to a 2021 report by the Food and Agriculture Organization of the United Nations (FAO). Although it was not quantitatively modelled in this policy, the blueprint toolkit does have a policy on incentivising reformulation of HFSS.

Changes in the prevalence of people living with obesity

Table 1 shows the percentage reduction of adults and children moving from BMI≥30 to a healthier BMI category following the introduction of a mandatory front-of-pack labelling. We are in the process of modelling the impact on children and will update findings upon completion.

Cost over 5 years

We estimated that this policy would cost the governments approximately £18 million over five years

Table 2 below shows a breakdown of costs. The direct costs to the governments of monitoring and enforcing is estimated at approximately £1.4 million per year and the cost of running a social marketing campaign is estimated at £2.2 million per year (totalling £18 million over five years). The costs to the food industry are estimated at approximately £2 million in the first year for familiarisation and around £4 million per year for three years to change the product labels. This policy would require the implementation of mandatory healthy food sales reporting, the costs of which are not included in this breakdown and are included as a separate policy: Data collection on healthiness of product portfolios.

Total annual benefit

We estimated that this policy would have an annual benefit of approximately £2 billion

Using analysis conducted by the Tony Blair Institute and Frontier Economics, we estimate this policy would result in benefits of £2 billion per year on average. Approximately two-thirds of this saving would benefit individuals (via quality-adjusted life years and informal social care). The remaining third relates to savings that benefit the state via NHS treatment costs, productivity and formal social care. See our Technical Appendix for more information about the cost breakdowns.