Background To tackle childhood obesity, the UK Government is consulting on prohibiting the advertising of high fat sugar salt foods (HFSS) on television between 0530 and 2100. We sought to estimate the health impact of this policy in the UK.

Methods Informed by a literature review, we adapted an existing multi-state lifetable model (PRIMETime) to model the impact of television advertising exposure on children’s caloric intake, and the subsequent impact on body mass index and health.

We used data from AC Nielsen and Broadcasters’ Audience Research Board data (2015) on children’s exposure to HFSS advertising (adopting the FSA-Ofcom definition of HFSS); published meta-analysis quantifying the effect of less-healthy food advertising on caloric intake in children; the Human Mortality Database for the UK (2015) on population numbers and all-cause mortality rates; the Health Survey for England (2016) on body mass index; the Global Burden of Disease Study for disability weights to estimate Disability Adjusted Life Years (DALYs).

We simulated a closed cohort of the UK population aged 0–17 years in 2015 (n=13,729,000), following the cohort to death. We assumed HFSS advertising had no effect on adults, and that changes in mean BMI observed at age 17 years persisted throughout adult life.

The main outcome measures were change in percentage of the children (aged 5–17 years) with obesity defined using International Obesity Task Force cut-points, and change in health status (DALYs). Monte Carlo analysis was used to estimate 95% uncertainty intervals.

We compared three scenarios:

1. All HFSS advertising between 0530 and 2100 is withdrawn

2. All HFSS advertising between 0530 and 2100 is displaced to 2100 to 0530

3. No intervention

Results If all HFSS advertising between 0530 and 2100 was withdrawn, we estimate that UK children would decrease caloric intake by 9.1kcal (95 CI: 0.5kcal-17.7kcal), which would reduce the number of children with obesity by 40,000 (12,000–81,000) or 4.6% (1.4%-9.5%) compared to no intervention. This would avert 240,000 (65,000–530,000) DALYs across the cohort’s lifetime. Under a scenario where all HFSS advertising is displaced to 2100 to 0530, we estimate that the benefits would be reduced by around two-thirds.

Conclusion Measures that reduce exposure to less-healthy food advertising on television, such as restricting HFSS advertising between 0530 and 2100, could make a meaningful contribution to reducing childhood obesity. The impact of this policy may be reduced if adverts are displaced to after 2100 rather than being withdrawn.