Adolescence and early adulthood are periods of major biological, economic and social transitions for rural youth. They provide a critical window of opportunity for addressing chronic nutritional deficits from childhood, for “catch-up” growth, for providing a solid foundation for a healthy productive and reproductive life, and for arresting the intergenerational transmission of malnutrition. In this study we show that rural transformation processes are associated with improvements in rural youth nutrition – malnutrition and underweight – in nearly all regions, although the pace of change varies considerably across countries. Most low- and middle-income countries (LMICs) are faced with the double burden of malnutrition and overweight/obesity, and in some countries this double burden is increasing, with the prevalence of underweight and overweight/obesity rising concurrently. The effect of rural transformation processes on rural youth nutrition is mediated by its effects on the external and personal domains of the “food environment”. Transformation of agri-food systems are bringing about large changes in the diets of rural youth in LMICs, and particularly of the younger age groups, who appear to be witnessing rapid dietary transitions. The Young Lives dataset suggest that certain near-universal changes in patterns of dietary and nutrient intake patterns can be discerned in LMICs, although the pace of change varies. Dietary transitions are also driven by “globalisation influences” – especially dissemination of information through digital/social media and food industry advertising and marketing strategies – even in countries with low/slow rural transformation. Our results show that rural transformation processes can have both positive and negative effects on rural youth nutrition in LMICs. Despite the globalisation influences of international trade and agri-food systems, dietary changes in individual LMICs are still influenced by national policies and production patterns. Understanding the pathways to impact of rural transformation on rural youth nutrition is crucial for designing “nutrition-sensitive” rural transformation policies.