Obesity has become a significant health concern worldwide. In England, 10% of children at reception age (4-5 years old) are obese, and this number increases to 20% among children in year six (10-11 years old).
Children who are obese have a higher risk of developing serious health issues such as high blood pressure, type II diabetes, and depression in both childhood and adulthood.
In the UK, young people consume excessive amounts of added sugar, with typical consumption of 70g per day by late adolescence, which is more than double the recommended limit of 30g.
A significant contributor to childhood obesity is the consumption of sugar-sweetened beverages. Children from disadvantaged households are particularly at risk of both obesity and excessive consumption of these drinks.
In an effort to combat childhood obesity and reduce excessive sugar intake, the UK government introduced a two-tier sugar tax on soft drinks in April 2018, known as the soft drinks industry levy. This tax was implemented to encourage manufacturers to lower the sugar content in their drinks.
Scientists from the Medical Research Council (MRC) Epidemiology Unit at the University of Cambridge conducted a study that monitored the changes in obesity rates among children in England, specifically those in reception year and year six, between 2014 and 2020. They analyzed the variations in obesity levels by comparing data 19 months after the implementation of the sugar tax, and taking into account previous trends in obesity rates.
The research team discovered that the sugar tax was linked to an 8% relative decrease in obesity levels among year six girls, which translates to preventing 5,234 cases of obesity per year within this group alone.
The reductions were the highest in girls who attend schools in deprived areas, where children are known to consume the most sugary drinks. Girls living in the most deprived areas experienced a 9% reduction in obesity.
However, there were no connections found between the sugar tax and changes in obesity levels among children in the reception age. In year six boys, there was no overall change in the prevalence of obesity.
Dr. Nina Rogers, the first author of the study from the MRC Epidemiology Unit at Cambridge, adds: “We urgently need to find ways to tackle the increasing numbers of children living with obesity, otherwise we risk our children growing up to face significant health problems. That was one reason why the UK’s soft drinks industry levy was introduced, and the evidence so far is promising. We’ve shown for the first time that it is likely to have helped prevent thousands of children each year becoming obese.
“It isn’t a straightforward picture, though, as it was mainly older girls who benefited. But the fact that we saw the biggest difference among girls from areas of high deprivation is important and is a step towards reducing the health inequalities they face.”
The researchers found an association, not a causal link, but this study supports earlier research that the sugar tax led to a significant reduction in the sugar content of soft drinks.
“We know that consuming too many sugary drinks contributes to obesity and that the UK soft drinks levy led to a drop in the amount of sugar in soft drinks available in the UK, so it makes sense that we also see a drop in cases of obesity, although we only found this in girls,” comments Senior author Professor Jean Adams.
“Children from more deprived backgrounds tend to consume the largest amount of sugary drinks, and it was among girls in this group that we saw the biggest change.”
The researchers suggest several reasons why the sugar tax did not result in changes in obesity levels among younger children. They explain that younger children consume less sugar-sweetened drinks than older children, so the impact of the soft drinks levy would have been less significant.
Additionally, fruit juices are not included in the tax, but they contribute similar amounts of sugar to young children’s diets as sugar-sweetened beverages. It is not clear why the sugar tax might have different effects on obesity rates in girls and boys, especially since boys tend to consume more sugar-sweetened beverages.
The researchers suggest one possible explanation is the impact of advertising. Several studies have found that boys are exposed to more food-related advertising than girls, through higher levels of TV viewing and how the advertisements are presented.
Boys also tend to be more likely to believe that energy-dense foods depicted in advertisements will improve physical performance, and are more likely to choose these energy-dense, nutrient-poor products when endorsed by celebrities.
The study was a collaboration of researchers from several universities including the University of Cambridge, the London School of Hygiene and Tropical Medicine, the University of Oxford, the Great Ormond Street Institute of Child Health and the University of Bath. The research was funded by the National Institute of Health and Care Research and the Medical Research Council.
Source: 10.1371/journal.pmed.1004160
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