Double-duty actions tackling undernutrition and overnutrition: A systematic review

Low- and middle-income countries (LMICs) are increasingly facing the double burden of malnutrition (DBM) because of rapid nutrition transition, which is driven by economic growth, urbanisation, globalisation, and technological change. Nutrition-specific and nutrition-sensitive interventions can directly or indirectly affect both undernutrition and overnutrition, with nutrition-specific approaches typically targeting the immediate causes of malnutrition and nutrition-sensitive ones focusing on the underlying factors. In response to global efforts to eliminate all forms of malnutrition by 2030, this systematic review looks at the risks and opportunities of double-duty actions in LMICs.

Twenty-six studies (20 nutrition-specific and six nutrition-sensitive interventions) with robust study designs were included. At least one indicator of overnutrition and undernutrition must have been reported on. All studies were classified based on their effect on DBM (ranging from beneficial to harmful).

The risk of inadvertently increasing maternal or child overnutrition was identified in seven out of eight maternal and child health interventions that provided a food-based or nutritional supplement. Behaviour change interventions, in both maternal and child health interventions (five studies) and school-based interventions (two studies), reported potential opportunities for double-duty actions. Two low-quality studies modifying school food environments reported a potential DBM benefit, for example providing incentives to increase the availability of healthy foods. Despite the overall potential DBM benefit of school-based interventions, the outcomes on growth in several studies lacked statistical significance, likely due to the short follow-up periods (three months to a year).

The effectiveness of conditional cash transfers in reducing stunting and underweight in LMICs is well documented, but few studies have examined their effects on overnutrition. Conditional cash transfers had a suggested beneficial effect on DBM in two out of four studies, but one low-quality study raised concerns about potential harmful effects on maternal overweight. Two longer-term studies evaluating social policies were classified as having a harmful effect on DBM.

The authors acknowledged several limitations. Only studies that reported on DBM outcomes were included (reporting bias) and it was not possible to complete a meta-analysis due to the wide range of interventions and outcomes. A lack of subgroup analysis, language constraints, and the authors’ summary of descriptive information introducing bias or oversight were also reported.

In summary, the authors identified that half of all the interventions reviewed, while having a positive effect on undernutrition, also had unintended harmful effects on overnutrition. There is considerable potential for adapting pre-existing nutrition-sensitive and nutrition-specific interventions to reduce the increasing DBM in LMICs. This could be achieved through consistently including dual objectives and measuring and reporting on both undernutrition and overnutrition outcomes in all nutrition interventions, regardless of the intervention’s target, in line with the indicators established under Sustainable Development Goal 2.2.