Childhood obesity is a risk factor for adult cardiovascular diseases and reduced life expectancy. It adversely impacts children, families, and society at personal and economic levels. Research shows that early life interventions targeted during pregnancy and early childhood have the potential to reduce overweight and obesity. There is strong evidence that the promotion of exclusive breastfeeding may help reduce the risk of overweight/obesity during childhood. Interventions showing positive impacts include those combining diet, exercise, and behavioral approaches, lasting more than 1 year and using personalized and culturally adapted methods in schools, households, or community settings. However, interventions individually targeting diet or physical activity during childhood have failed to show impacts on obesity at the populational level. Efforts are needed to promote healthy lifestyles outside of the school settings, including at household, social, and public health levels to break the cycle of overweight and obesity. Achieving appropriate pregnancy and infancy weight gains, as well as weight management during childhood and adolescence, will lead to a healthier society.