(also called an "enabling environment") applying several nutritional modifications or changes in a population on a large scale which have a high benefit and a low cost a strong foundation that can drive change (food security, and a supportive health environment through increasing access to safe water and sanitation). To prevent stunting, it is not just a matter of providing better nutrition but also access to clean water, improved sanitation (hygienic toilets) and hand washing at critical times (summarised as "WASH"). Without provision of toilets, prevention of tropical intestinal diseases, which may affect almost all children in the developing world and lead to stunting will not be possible. Studies have looked at ranking the underlying determinants in terms of their potency in reducing child stunting and found in the order of potency: percent of dietary energy from non-staples (greatest impact) access to sanitation and women's education access to safe water per capita dietary energy supply Three of these determinants should receive attention in particular: access to sanitation, and diversity of calorie sources from food supplies. A study by the Institute of Development Studies has stressed that: "The first two should be prioritized because they have strong impacts yet are farthest below their desired levels". The goal of UN agencies, governments and NGO is now to optimise nutrition during the first 1000 days of a child's life, from pregnancy to the child's second birthday, in order to reduce the prevalence of stunting. The first 1000 days in a child's life are a crucial "window of opportunity" because the brain develops rapidly, laying the foundation for future cognitive and social ability. Furthermore, it is also the time when young children are the most at risk of infections that lead to diarrhoea. It is the time when they stop breast feeding (weaning process), begin to crawl, put things in their mouths and become exposed to faecal matter from open defecation and environmental enteropathies. Dietary interventions to improve stunting Previous interventions to reduce stunting have shown modest effects. Multiple micronutrient supplementation shows only small benefits for linear growth and results from studies supplementing lipid based nutrient supplements (LNS) to children are inconclusive. Educational interventions to improve complementary feeding may achieve behavioral change but have no or small effects on growth. Further, studies on the effect of micronutrient fortification, increased availability of key nutrients or increased energy density of complementary foods on stunting also show