GCRF Action against Stunting Hub The global community aims to decrease the number of stunted children under five by 40% by 2025. While targeted and specific, we know that this is presently unachievable. Part of the problem is that over the last three decades, the search for the 'silver bullet' or the specific driver, which if addressed could solve this intractable problem, has narrowed praxis. This is not to say that gains have not been made, but rather our efforts have not been entirely impactful. While substantial disciplinary advances have occurred, often they have not been joined-up. And while systematic reviews abound, pan-disciplinary understandings, do not. Hence, child stunting is an intractable problem, waiting for a unified solution.   If we perceive child under-nutrition as a mosaic, we have knowledge of many of the individual elements. For example, biological advances demonstrate there is an identifiable 'epigenetic signature' of stunting. Children who are stunted also have immature gut micro-biomes and we also know a large proportion of the global malnutrition burden is caused (either directly or indirectly), by infectious agents ranging from viruses and bacteria to protozoa and helminths. Food-borne toxins also impact stunting. Equally, we know a range of elements can help to prevent stunting from animal source Foods (ASF) to behavioural elements from dietary choices to feeding practices to water, sanitation and hygiene (WASH). Yet overall, it may be argued that we are missing the shape and structure of the mosaic and the synergies between the component parts. In many quarters, the literature on child under-nutrition is viewed as 'siloed' and non-relational (Perkins et al., 2017). But equally importantly, 'integrated' nutritional programmes have often not had the expected impacts.  Herein lies the problem and the related solution: we urgently need to understand the 'cascade' of factors driving child stunting and the synergies and inter-relationship between drivers. And equally importantly, we need to better understand the 'tipping points' or the critical points along this cascade where healthy linear growth diverges to slow or no growth. To do this, we propose to transform our exploration of child under-nutrition from the component parts to the 'whole child'. Where the biological, social, environmental and behavioural context in which stunting occurs is understood in its entirety and where the strength and directionality of these drivers, inform related interventions. Based on this joined-up approach, we will explore the ability of a range of child-centred interventions to disrupt the cascade of factors that inhibit the ability of a child to grow. These actions and outcomes will then form the basis of a decision-making platform to enable users to identify the ex-ante and ex-post impacts of potential interventions. Embedded in this process, however, is a values-based approach that ensures that from the outset, our research directly connects to and betters the lives of the children, families and communities involved.   We will work across three countries: India, Indonesia and Senegal in over 50 communities. We aim to decrease child stunting by up to 10% our communities. Finally, to enhance our impact and legacy our Hub, we will engage a range of end-users in both our outputs and in the wider 'whole child' approach. We will support new regional platforms on maternal and child nutrition proposed by UNICEF linking the work of FAO/The World Bank/WHO at the country-level. We will also engage our network of over 100 civil society organizations in our findings. Over the course of the project, we expect to positively impact the lives of up to 1 million children. The Global Challenges Research Fund (GCRF) supports cutting-edge research to address challenges faced by developing countries. The fund addresses the UN sustainable development goals. It aims to maximise the impact of research and innovation to improve lives and opportunity in the developing world.