Why is this review important?
As outlined by the World Health Organization, 'globesity' (the rise in overweight and obesity globally) is a major world challenge. A sugar‐rich diet, especially when combined with physical inactivity, may cause overweight and obesity, and other harmful health outcomes. There are direct costs to healthcare services of people being overweight or obese, such as preventing and treating health problems that this causes. There are also costs to society as a whole when people who are ill through being overweight or obese are unable to work.
Who will be interested in this review?
This review may be of interest to government public health agencies, policy decision‐makers, food retailers, and food industries. This review and subsequent updates of this review may change policy and affect a government's motivation to create a tax on unprocessed sugar and foods with added sugar. It also may motivate food industries to reformulate their products to contain lower levels of added sugar.
What question does this review aim to answer?
We wanted to know if taxation of unprocessed sugar and foods with added sugar (other than sugar‐sweetened beverages (SSBs)) reduced their consumption, changed people's energy intake, and reduced overweight and obesity. We also wanted to know if taxation changed people's diet and spending, and had an effect on other diet‐related health problems.
Which studies were included in the review?
We searched for ongoing or published studies up to October 2019. Of a total of 24,454 records retrieved, we identified one 'interrupted time series' (ITS) study meeting our eligibility criteria to assess the impact of a tax on sugar‐added foods (but not unprocessed sugar). The study used data from the Hungarian Household Budget and Living Conditions Survey, with observations from 40,210 households. Evidence from the study included a 'baseline' (the situation before taxation), ranging from January 2008 to August 2011. The Hungarian public health product tax was implemented on September 2011. The duration of the follow‐up period (measuring the effects of taxation) was 16 months. The study was funded by the Scottish Institute for Research in Economics (SIRE) Early Career Engagement Grant.
What does the evidence from the review reveal?
The included study provided very limited evidence that taxing foods with added sugar reduced their consumption by 4%. We are very uncertain about this evidence because the study did not use the strongest methods, looked at other kinds of taxation as well as taxing foods with added sugar, and may not have correctly classified food types. We are uncertain whether taxing foods with added sugar has an effect on reducing their consumption. The included study did not investigate the effects of taxing unprocessed sugar.
What should happen next?
Further research is needed to assess the effectiveness of taxing unprocessed sugar or foods with added sugar for reducing their consumption and preventing obesity or other adverse health outcomes. Studies should take place in countries that have implemented these taxes and should look at cost‐effectiveness as well as the health benefits of taxing unprocessed sugar or foods with added sugar as a public health policy for preventing overweight, obesity or other adverse health outcomes. Countries that have implemented these taxes are Bermuda, Dominica, Hungary, India, Norway, the Navajo Nation (USA), and St. Vincent and Grenadines.
Read the full review here