On World Obesity Day, 4 March, we highlight the success Portugal has had in tackling childhood obesity – one of the main health challenges in the WHO European Region – with their sugary drinks tax.

Childhood obesity is a complex public health issue – caused by many factors, it intersects significantly with socioeconomic status. As obesity can establish behaviours at a young and vulnerable age, countries have a duty to protect children from a phenomenon that can become a health burden for the rest of their lives.

In Portugal, the combination of unhealthy diets and a rise in sedentary lifestyles has precipitated a public health struggle with childhood obesity. The consequences of this have implications for Portugal to achieve the wider targets for noncommunicable diseases (NCDs) by 2030.

The importance of monitoring health trends

However, one monitoring programme, the WHO European Childhood Obesity Surveillance Initiative (COSI), has attempted to take a firm hold on the crisis. COSI has been tracking the trend in childhood obesity for 12 years and has seen the numbers in Portugal slowly but surely turn around. COSI is an initiative that has surveyed the weight of school-aged children every 2–3 years in over 40 Member States of the European Region since 2008. It has delivered invaluable data to governments across the Region in that time.

Dr Ana Rito, Portugal’s Principal Investigator for COSI, walks us through the component parts of this critical monitoring initiative. “Between 2008 and 2016 we can see a drop in overweight children [in Portugal] from 37.9% to 30.7% and in obese children from 15.3% to 11.7%. However, it remains one of the highest rates in Europe,” she explains. Thanks to COSI, it is not just prevalence that can be assessed but also the behavioural aspects of healthy lifestyles, including diets and physical habits. It also goes beyond the children themselves to assess their environments, such as schools and family. This detailed level of analysis showed that despite the decreasing rates of obesity overall, dietary patterns seemed resistant to change.

Healthy lifestyles

Most importantly, COSI identified one of the main culprits. It seemed that the number of children who regularly drink soft drinks – a significant influence on weight gain – had increased over time to reach over 80.1% of children aged 6–8 years in 2016. “This data provided scientific evidence essential to support the implementation of the sugary drinks tax,” Ana tells me.

Taxation is often an effective way of nudging behaviour change and is far more successful than targeting or shaming individuals. However, building political momentum for such legislative change often proves challenging, particularly when it tackles an industry which puts profit before the health priorities of young people. Nonetheless, leading public health institutions in Portugal helped drive taxes on sweet beverages up the agenda and in January 2017, Portugal brought into force a sugary drinks tax.

Big steps forward

The results are impressive. Many companies have radically reduced the amount of sugar in their products and sales of sugary drinks have fallen overall. Future rounds of the COSI Portugal study will be able to track the full impact on children’s consumption patterns, but the initial plunge in high-sugar beverage sales and the significant reformulation of products is impressive.

Dr Francisco Goiana Silva was in the cabinet of the Ministry of Health of Portugal when the sugary drinks tax was implemented and is confident about the tax: “this policy intervention is estimated to have had a far greater impact on the population’s diet than all the education and self-regulated mechanisms combined. The tax also serves as a measure to tackle health inequalities”. Unhealthy diets and obesity are strongly related to social determinants of health in Portugal – people at lower income and education levels are the most vulnerable to developing NCDs. “By promoting transfer of consumption to healthier choices, such as water, which is not more expensive, this policy will reduce the risk of developing NCDs among the most vulnerable population groups,” added Dr Silva.

Dr Silva also stresses the importance of investing revenue raised by the sugary drinks tax in health promotion initiatives. “It allows the creation of a multiplier effect,” he said. “It brings to light the positive impacts of the tax and prevents criticism from stakeholders in the industry arguing that the tax serves only to generate revenue.”

Surveillance systems such as COSI are clearly not just monitors of change – they have a huge amount of agency in driving through reforms and building change themselves. When policy-makers, politicians and academics collaborate flexibly, they can have a significant impact on influencing the healthy behaviour of populations.

COSI is just one of the WHO tools that Portugal has adopted to tackle childhood obesity and other NCD risk factors. National-level stakeholders have recognized the importance of such tools and resources. “Having tools which can be readily used by policy-makers and ministries of health to assess the potential impact of policy scenarios is extremely useful. In the past, we have also used WHO tools to estimate the potential health impact of the Portuguese Sweetened Beverages Tax and we are currently considering their application in other policies,” commented Dr Maria João Gregório, Director, Portuguese National Programme for the Promotion of Healthy Eating.

Portugal’s fiscal measures are taking on entrenched challenges and defending the right to health for all – including children. Although there is more work to be done on healthy behaviours, these measures offer a guide to best practice in turning the tide of the childhood obesity epidemic.