Limiting the hours of television advertising for foods and beverages high in fat, sugar and salt (HFSS) could make a meaningful contribution to reducing childhood obesity, according to a study published by Oliver Mytton of the University of Cambridge, UK, and colleagues.
"Our analysis shows that introducing a 9 p.m. watershed on unhealthy TV food advertising can make a valuable contribution to protecting the future health of all children in the UK, and help level up the health of children from less affluent backgrounds," said Mytton. "However, children now consume media from a range of sources, and increasingly from online and on-demand services, so in order to give all children the opportunity to grow up healthy it is important l to ensure that this advertising doesn't just move to the 9-10 p.m. slot and to online services."
Watching unhealthy food advertising increases the calories children eat. While greater calorie intake increases the likelihood of a child gaining excess weight, little is known about the impact of advertising on childhood obesity and overweight, the authors noted. Restrictions on television advertising of unhealthy food are actively being considered in the UK to help prevent childhood obesity; the impact of these proposed restrictions is unknown.
In the study – reported in the paper - ‘The potential health impact of restricting less-healthy food and beverage advertising on UK television between 05.30 and 21.00 hours: A modeling study’, published in PLOS Medicine, the researchers used data on children's exposure to HFSS advertising during these hours, as well as previously published information on the association between exposure to HFSS advertising and children's caloric intake.
Using a proportional multi-state life table model, the researchers were able to estimate the health impact of prohibiting the advertising of food and beverages high in fat, sugar, and salt (HFSS) from 05.30 hours to 21.00 hours (5:30 AM to 9:00 PM) on television in the UK. Monte Carlo analyses was used to estimate 95% uncertainty intervals (UIs). The main outcome measures were change in the percentage of the children (aged 5–17 years) with obesity defined using the International Obesity Task Force cut-points and change in health status (DALYs). They used the following data to parameterise the model:
- children’s exposure to HFSS advertising from AC Nielsen and Broadcasters’ Audience Research Board (2015)
- effect of less-healthy food advertising on acute caloric intake in children from a published meta-analysis
- population numbers and all-cause mortality rates from the Human Mortality Database for the UK (2015)
- body mass index distribution from the Health Survey for England (2016); disability weights for estimating disability-adjusted life years (DALYs) from the Global Burden of Disease Study
- and healthcare costs from NHS England programme budgeting data.
The researchers estimated that if all HFSS advertising between 05.30 hours and 21.00 hours was withdrawn, UK children (n=3,729,000), would see on average 1.5 fewer HFSS adverts per day and decrease caloric intake by 9.1 kcal (95% UI 0.5–17.7 kcal), which would reduce the number of children (aged 5–17 years) with obesity by 4.6% (95% UI 1.4%–9.5%) and with overweight (including obesity) by 3.6% (95% UI 1.1%–7.4%).
This is equivalent to 40,000 (95% UI 12,000–81,000) fewer UK children with obesity and 120,000 (95% UI 34,000–240,000) fewer with overweight. For children alive in 2015 (n=13,729,000), this would avert 240,000 (95% UI 65,000–530,000) DALYs across their lifetime (i.e., followed from 2015 through to death), and result in a health-related net monetary benefit of £7.4 billion (95% UI £2.0 billion–£16 billion) to society.
Under a scenario where all HFSS advertising is displaced to after 21.00 hours, rather than withdrawn, they estimate that the benefits would be reduced by around two-thirds.
The study only considered the direct impact of HFSS advertising on children's caloric intake and did not consider the impact of HFSS advertising on changing both children's and adults' dietary preferences and habits.
However, the researchers acknowledged that: “This is a modelling study and subject to uncertainty; we cannot fully and accurately account for all of the factors that would affect the impact of this policy if implemented. Whilst randomised trials show that children exposed to less-healthy food advertising consume more calories, there is uncertainty about the nature of the dose–response relationship between HFSS advertising and calorie intake.”
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