This paper reviews information on why the nutrition of older children (5–9 years) and adolescents (10–19 years) is important and the consequences that it can have over generations. Developing countries still face a high burden of undernutrition and anemia, while the burden of overweight and obesity is on the rise in both developing and developed countries. There are evidence-based interventions which can improve the nutritional status and these include interventions for a balanced and diverse diet and micronutrient supplementation, especially iron and multiple micronutrient supplementation where there is sufficient evidence to reduce anemia. There is mixed evidence for the effective strategies to prevent and control obesity and a dearth of evidence from developing countries. Adolescent pregnancy also poses greater challenges to the health of mother and child, and advocacy should be rampant to delay the age of marriage and pregnancy. Interventions targeted to improving the nutritional status among “pregnant adolescents” have shown improvement in birth weight and a reduction in low birth weight and preterm delivery. Traditional platforms including school-based and community-based approaches offer a mixed picture of effectiveness, but emerging avenues of mHealth and social media could also be channelized to reach this population. The population of this age group is on the rise globally, and failure to invest in improving the nutrition of older children and adolescents will further increase the number of dependents in coming generations and negatively influence the health of future generations and progress of nations.