Sugar tax proving effective

But there's a stark difference between boys and girls.....
03 February 2023

Interview with 

Jean Adams, University of Cambridge


A glass of Coke and ice


According to the 2021 Health Survey for England, almost three quarters of UK adults are overweight or obese, with obesity rates doubling in the last 30 years. Apart from this being an alarming trend in its own right, the evidence is that young children are also affected, with roughly a third of 10 and 11 year olds overweight or obese. And as they grow up, these children are likely to remain overweight adding to the prevalence of obesity within the population. It's the biggest risk factor for conditions like diabetes and heart disease, which now cost the health service billions every year.

Sugar consumption has been blamed as a major culprit, and most teenagers are typically consuming over 70g of refined sugars every day - that's double the recommended amount. Most of the intake is coming from sugar-sweetened drinks. This is what prompted the government to introduce a "sugar tax" in 2018 to penalise manufacturers based on how much sugar they put in their beverages. So has this intervention worked? Jean Adams from the Cambridge MRC Epidemiology Unit has been looking at the impact on school-age children.

She’s analysed data from the National Child Measurement Programme on over 1 million children in reception - that's 4 to 5 years old - and year 6 - that's 10 to 11 years old - in English primary schools. The introduction of the sugar tax, she's found, was associated with an 8% relative reduction in obesity levels in year six girls; this is equivalent to preventing 5,234 cases of obesity per year in this group. The reductions were greatest in girls whose schools were in deprived areas, where children are known to consume the largest amount of sugary drinks. Surprisingly, boys though showed no change in obesity rates...

<>Jean - We have about 50 countries or territories around the world which now have a tax on soft drinks or sugary drinks. And there is now quite a lot of evidence that they lead to reductions in purchasing and consumption of the drinks that are taxed. There's less data so far on impacts on hard health outcomes. So this study that we've done on obesity in children is kind of leading the way there.

James - Okay. So the signs are good, the tax is making a difference, but how do you know for sure that it's the sugar tax doing this and not other things? Messaging? Education?

Jean - Yeah, that's a really good question and it is really difficult to untangle these things. It's very difficult to get clear signals from this sort of policy evaluation where we're looking in the real world rather than doing controlled trials. And I guess there's a number of ways to think about that and one might be that the messaging and the education is part of what the tax is. So when we introduce a tax that comes along with a lot of discussion in the media, in other places about why is the government taxing soft drinks, well that's because they think they're not very good for you. And so we can think of that whole package of measures as part of what the tax is, but also the methods that we've used where we look at trends over time and how those change in relation to when the tax was implemented. A real problem with that sort of method is it is vulnerable to other things happening.

Jean - So we can't say for absolute certain the tax has led to the change in obesity levels that we see, but we can say that it's part of a jigsaw of lots of different pieces of emerging evidence. So we saw that coincident with the tax coming in, we saw changes in the amount of sugar that was in drinks and that reflects that the tax encouraged manufacturers to reduce the sugar in their drinks. And we also saw decreases in purchasing of sugarery drinks. So all these things together make us think that there's a story to be told.

James - Sure. Just to rewind back a bit slightly. Have you got numbers to put on this as to how exactly important the tax was in reducing sugar intake in kids?

Jean - We have not yet looked at sugar intake in totality, we've looked at purchasing of drinks in households and we see a reduction there in the kind of 5% range.

James - And is it affecting everyone the same? Boys, girls why the difference there? I mean, perhaps you don't have the answer for me right now, but could you speculate as to why you're seeing that difference?

Jean - Yeah, we don't know the answer to that and this data doesn't tell us. So it really is speculation. But I guess we all know that we live in society where girls and boys experience life differently. So girls may be primed to be more responsive to messages about what they're eating, what they look like. Boys might be more primed to messaging about what it is to be good at sport and how energy drinks play into that.


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