Food and diet

Sugar tax would 'cut childhood obesity'

"Sugary drinks tax 'will benefit children most'," BBC News reports. A new study, where researchers tried to estimate the impact of a sugar tax on soft drinks, found that it would help combat child obesity as well as tooth decay.

A proposed UK sugar tax on soft drinks is expected to be introduced in 2018.

By modelling three scenarios the researchers found that the maximum health benefits would be seen if products were changed to contain less sugar. This option was estimated to help reduce obesity cases in the UK by around 150,000 per year, as well as reducing cases of tooth decay by 250,000.

However, these are estimates only, not certain effects. And changing the sugar content of sweetened drinks could only have such an effect on those who continue to consume high amounts of sugar through other dietary sources.

If you would like to reduce the amount of sugar you or your children consume through drinks, you don’t have to wait until 2018. You can simply swap sugary fizzy drinks or sugary squash for water, lower-fat milks, or sugar-free, diet and no added sugar drinks. And if you prefer to have fizzy drinks, try diluting fruit juice with sparkling water.

Read more about cutting sugar from your diet.

Where did the story come from?

The study was carried out by researchers from a number of institutions, including the University of Oxford and the University of Cambridge School of Clinical Medicine. No sources of funding were reported.

The study was published in the peer-reviewed medical journal The Lancet.

This study has been widely, and generally accurately, reported in the UK media, providing the main findings of the study. The Guardian also tries to add some balance by providing quotes from Gavin Partington of The British Soft Drinks Association. "The problem with this modelling is that it is based on the flawed concept that obesity can simply be attributed to calorie or sugar intake per se and consumption of one product in particular, rather than overall lifestyle and diet."

He went on to say: "This error is plain to see given that sugar intake from soft drinks has been declining for several years now, down 17% since 2012. There is no evidence worldwide that a tax on soft drinks has had an impact on levels of obesity."

What kind of research was this?

This was a modelling study that aimed to assess the health effects of the sugar tax for soft drinks proposed earlier this year. This is where high tax would be placed on high-sugar drinks containing more than 8g of sugar per 100ml, moderate tax for mid-sugar drinks with 5-8g, and no tax for low-sugar drinks with less than 5g per 100ml.  In particular they aimed to estimate the effect on number of cases of obesity, diabetes and oral health.

While this study may provide some interesting findings it should be noted that this is a model based on assumptions, which cannot prove what would happen in real life.

What did the research involve?

The researchers modelled three scenarios to estimate what would happen if drinks were reformulated to reduce sugar concentration; if the price was increased by taxation; or if there were changes to the market share of high-sugar, mid-sugar and low-sugar drinks. For each of the scenarios a best and worst case scenario was modelled.

When modelling reformulation, the best case scenario assumed a 30% reduction in sugar concentration in high-sugar drinks and 15% reduction in mid-sugar drinks. The worst case scenario assumed a 5% reduction in sugar concentration of both high-sugar and mid-sugar drinks.

The price change scenarios assumed a levy of 18p per litre on mid-sugar drinks and 24p on high-sugar drinks. No tax was applied to low-sugar drinks. The best case for price change assumed that only sugar-sweetened beverages had tax applied, with a price increase of around 20% for consumers, and in the worst case the tax is evenly applied to all soft drinks, including diet drinks, fruit juice and bottled water, resulting in a 6% price rise.

When modelling redistribution of the market share, high-sugar drinks would need to fall by 12% alongside a 6% increase for each of mid-sugar and low-sugar drinks. The worst case factored in that increased marketing of new mid-sugar drinks might lead consumers to switch to this category from low-sugar drinks.

What were the basic results?

The researchers estimated that the best case scenario for drinks reformulation would produce an annual result of 144,383 fewer adults and children with obesity in the UK; 19,094 fewer cases of type 2 diabetes; and 269,375 fewer decayed, missing or filled teeth.

An increase in the price of sugar-sweetened beverages in the better case scenario would result in 81,594 fewer adults and children with obesity; 10,861 fewer new cases of diabetes; and 149,378 fewer decayed, missing, or filled teeth.

Changes to market share to increase amount of low-sugar drinks sold in the better-case scenario saw 91,042 fewer adults and children with diabetes; 1,528 fewer new cases of diabetes; and 172,718 fewer decayed, missing, or filled teeth per year.

The greatest benefit for obesity and oral health would be for those under 18 years of age, with the largest overall decreases in cases of diabetes being in those above 65 years.

How did the researchers interpret the results?

The researchers conclude: "The health impact of the soft drinks levy is dependent on its implementation by industry. Uncertainty exists as to how industry will react and about estimation of health outcomes. Health gains could be maximised by substantial product reformulation, with additional benefits possible if the levy is passed on to purchasers through raising of the price of high-sugar and mid-sugar drinks and activities to increase the market share of low-sugar products."


This modelling study aimed to estimate the possible health effects related to industry responses to the sugar tax proposed for soft drinks.

The research suggests that the largest health benefits might be seen if products were reformulated to contain less sugar. Additional benefits were seen if some of the tax from high- and mid-sugar drinks was passed on to the consumer, and activities to increase the market share of low-sugar products.

It would make sense that these measures would result in positive health effects. However, this is only a modelling study, and while the researchers have attempted to make these estimates as true to life as possible, they cannot be completely accurate. Sugar-sweetened beverages, though commonly consumed by children and young people, are only one source of sugar. If sugar is still being consumed in high amounts through confectionery, baked goods, in ready-made meals and sauces, or added sugar to food and drinks, then this may not have such great effect.

Current recommendations are that free sugars should not exceed 5% of our total dietary energy intake. This applies to all age groups from two years upwards.

In real terms, this means:

  • no more than 19g a day of free sugars for children aged four to six
  • no more than 24g a day for seven to 10-year-olds
  • no more than 30g a day for children from age 11 and adults

Read more about reducing sugar in the amount you, and your children, eat and drink.

NHS Attribution