When it comes to reducing obesity, evidence shows that changing food environments is more effective than measures that try to educate or change the behaviour of individuals. The interventions that participants consider to be most acceptable are the same as those that they perceived to be most effective at tackling obesity. However, the interventions that were reported to be least effective and least acceptable — such as reducing portion sizes and the taxation of unhealthy foods — may actually have the greatest potential for promoting healthy eating at the population level. While we must be cautious with how we interpret correlations like this, it suggests that addressing the disconnect between the evidence base and public understanding may be a viable way of influencing public acceptability

In this study, a 10% increase in SSB prices was associated with a 3% relative decrease in prevalence of overweight or obesity among adolescent girls. Improved weight-related outcomes were small and largely observed in girls with heavier weight and in cities where price increases were greater than 10% after the tax.

The evidence shows that this kind of behaviour change needs to happen collectively, not just individually. So we need joined-up governance at local, national and international levels. Food systems also contribute significantly to greenhouse gas emissions. This can be addressed by reducing waste or directing it back into the supply chain. A mix of different measures will be most effective. The evidence shows that taxation is one of the most effective ways to modify behaviour. Accreditation and labelling schemes can also have an impact.