Child and adolescent obesity has significantly increased globally within one generation. In the USA, children's average weight has risen by over 5 kg in three decades, with a third of children being overweight or obese. Similar or faster increases are reported in some low- and middle-income countries, despite high levels of undernutrition. Nutrition policies must promote healthy growth, household nutrition security, and protect children from sedentary activities and unhealthy foods. The governance of food supply and markets should be improved to protect children's health. The prevalence of childhood obesity has risen rapidly in many high-income countries, with data showing a significant increase in low- and middle-income countries. Surveys indicate a rapid rise in overweight prevalence among children and adolescents. While some high-income countries may have plateaued in obesity prevalence, it remains a significant health burden. The World Health Assembly set a global target to halt the rise of diabetes and obesity in adults and children. Key messages include the need for policies that address both undernutrition and obesity, ensuring healthy growth and nutrition security. Strategies should avoid increasing undernourishment and focus on promoting healthy diets and physical activity. Agricultural, food supply, and food environment targets are needed, with increased government involvement. Child obesity prevention requires multi-strategy interventions focusing on meals, classroom activities, sports, and play. These interventions should involve home, school, and community participants. However, there is a need for more research in diverse settings and to test comprehensive approaches. Most studies have been conducted in high-income countries, creating a bias in the literature. Cost-effectiveness studies show that some interventions are cost-effective, with a few being dominant in terms of health gains and cost savings. However, there is a lack of data on the cost-effectiveness of interventions in low- and middle-income countries. The economic impact of obesity includes increased healthcare costs and reduced productivity. Energy balance in childhood is complex, with interventions showing small but significant reductions in BMI. The need for significant weight reduction in older children is greater, and interventions targeting overweight and obese children require larger energy intake reductions. Nutrition policies must address both undernutrition and obesity, ensuring healthy growth and preventing poor nutrition. Dietary diversity and nutrient density are important for healthy growth. Policies should promote healthy diets and prevent overnutrition, especially in low- and middle-income countries. Food markets and commercial interests play a significant role in shaping children's diets. The promotion of unhealthy foods and beverages, especially to children, is a major concern. Governments and development agencies need to regulate food markets to protect children's health. Food environments and commercial interests are critical in shaping children's diets. Marketing of unhealthy foods and beverages to children is a major issue, with significant increases in advertising. The food industry has a special interest in targeting children, influencing their dietary preferences and brand loyalty. Nutrition policy, governance, and accountability are essential for preventing stunting and obesity. Integrated nutrition policies focus on providing children with the means to achieve optimal growth. Food supply targets mustChild and adolescent obesity has significantly increased globally within one generation. In the USA, children's average weight has risen by over 5 kg in three decades, with a third of children being overweight or obese. Similar or faster increases are reported in some low- and middle-income countries, despite high levels of undernutrition. Nutrition policies must promote healthy growth, household nutrition security, and protect children from sedentary activities and unhealthy foods. The governance of food supply and markets should be improved to protect children's health. The prevalence of childhood obesity has risen rapidly in many high-income countries, with data showing a significant increase in low- and middle-income countries. Surveys indicate a rapid rise in overweight prevalence among children and adolescents. While some high-income countries may have plateaued in obesity prevalence, it remains a significant health burden. The World Health Assembly set a global target to halt the rise of diabetes and obesity in adults and children. Key messages include the need for policies that address both undernutrition and obesity, ensuring healthy growth and nutrition security. Strategies should avoid increasing undernourishment and focus on promoting healthy diets and physical activity. Agricultural, food supply, and food environment targets are needed, with increased government involvement. Child obesity prevention requires multi-strategy interventions focusing on meals, classroom activities, sports, and play. These interventions should involve home, school, and community participants. However, there is a need for more research in diverse settings and to test comprehensive approaches. Most studies have been conducted in high-income countries, creating a bias in the literature. Cost-effectiveness studies show that some interventions are cost-effective, with a few being dominant in terms of health gains and cost savings. However, there is a lack of data on the cost-effectiveness of interventions in low- and middle-income countries. The economic impact of obesity includes increased healthcare costs and reduced productivity. Energy balance in childhood is complex, with interventions showing small but significant reductions in BMI. The need for significant weight reduction in older children is greater, and interventions targeting overweight and obese children require larger energy intake reductions. Nutrition policies must address both undernutrition and obesity, ensuring healthy growth and preventing poor nutrition. Dietary diversity and nutrient density are important for healthy growth. Policies should promote healthy diets and prevent overnutrition, especially in low- and middle-income countries. Food markets and commercial interests play a significant role in shaping children's diets. The promotion of unhealthy foods and beverages, especially to children, is a major concern. Governments and development agencies need to regulate food markets to protect children's health. Food environments and commercial interests are critical in shaping children's diets. Marketing of unhealthy foods and beverages to children is a major issue, with significant increases in advertising. The food industry has a special interest in targeting children, influencing their dietary preferences and brand loyalty. Nutrition policy, governance, and accountability are essential for preventing stunting and obesity. Integrated nutrition policies focus on providing children with the means to achieve optimal growth. Food supply targets must