Universal, whole system and settings-based interventions for stabilising or reducing the prevalence of overweight and obesity: a review of systematic reviews

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Introduction

The prevalence (how common something is at a specific time) of overweight and obesity in Wales is rising. Being overweight or obese increases a person’s risk of getting a range of chronic diseases such as type 2 diabetes, hypertension, and cardiovascular disease. 

We conducted a review of systematic reviews to examine what works in terms of universal, whole system and settings-based interventions (see glossary for definitions), for stabilising or reducing the prevalence of overweight and obesity. This work was undertaken to inform interventions, policies, and programmes within Wales to help reduce the burden of disease for key conditions such as diabetes and cardiovascular disease which are commonly caused, or made much worse, by obesity. 

Main points

How up to date is the evidence?

We conducted this review in 2024 and included evidence published between 2017 and 2024.

What we found

Overall, we found the evidence relating to the effectiveness of specific types of universal, whole system or settings-based interventions to be generally lacking, have differences in findings or not conclusive. Despite this, we are moderately confident that:

• School gardening programmes are effective for increasing fibre intake (summary 4.7.10). 
• Increasing the availability of low-calorie beverages in homes can reduce sugar sweetened beverage consumption amongst children (summary 4.7.14). 
• School based computer delivered nutrition interventions are effective for reducing sugar sweetened beverage intake, but moderate to good quality evidence suggests they are likely to be ineffective for reducing BMI (summary 4.7.8).

In addition, we also found that:

• In adults, workplace dietary behaviour change interventions with environmental, educational, or behavioural components (or a combination) can increase how much fruit and vegetable people eat. However, the poor methodological quality of studies exploring these interventions dids limit our confidence in this (summary 4.6.1). 
• In schools, interventions to reduce the availability of sugar sweetened beverages, or interventions to increase the provision of fruit may be effective for reducing how much sugar sweetened beverage children drink. However, this is not conclusive due to small numbers of studies (summary 4.7.3). 

Behaviour change interventions (using behavioural insights) in schools may be effective for increasing children’s fruit and vegetable intake. However, this is not conclusive due to poor study quality. There were no significant differences in effectiveness between interventions utilising different behavioural insights (summary 4.7.5).  

What this means

Despite the mixed findings, there are some interesting interventions that could be worthy of further investigation and consideration. This could be achieved by conducting further, more focused reviews of primary evidence as well as further in-depth evaluation of interventions.

The differences between interventions made comparisons difficult, and as the quality of reviews was generally considered poor to moderate, more well conducted studies investigating interventions specific to Wales are needed. 

Technical information

We conducted a review of systematic reviews following rapid systematic review methodology. We searched for systematic reviews assessing universal (population level), whole system or settings-based programmes aiming to stabilise or reduce the prevalence of overweight and obesity in children and adults.

Glossary

Universal interventions are those that can be applied to an entire population, with inclusion criteria simply being that a person is part of a defined population.

Whole system interventions are defined as population level multi-strategy interventions delivered across entire communities, comprising of system wide changes.

Settings based interventions are those that take place within a certain defined setting such as within schools or workplaces.

Rapid review: Is a form of evidence synthesis that accelerates the process of conducting a traditional systematic review to produce evidence in a time-sensitive manner, usually to inform urgent healthcare decisions.

Systematic review: A review that summarises the evidence on a clearly formulated review question according to a predefined protocol, using systematic and explicit methods to identify, select and appraise relevant studies, and to extract, analyse, collate and report their findings. It may or may not use statistical techniques, such as meta-analysis