Growth and development are key characteristics of childhood and sensitive markers of health and adequate nutrition. The first 1000 days of life-conception through 24 months of age-represent a fundamental period for development and thus the prevention of childhood obesity and its adverse consequences is mandatory. There are many growth drivers during this complex phase of life, such as nutrition, genetic and epigenetic factors, and hormonal regulation. The challenge thus involves maximizing the potential for normal growth without increasing the risk of associated disorders. The Mediterranean Nutrition Group (MeNu Group), a group of researchers of the Mediterranean Region, in this Special Issue titled "Prevent Obesity in the First 1000 Days", presented results that advanced the science of obesity risk factors in early life, coming both from animal model studies and studies in humans. In the future, early-life intervention designs for the prevention of pediatric obesity will need to look at different strategies, and the MeNu Group is available for guidance regarding an appropriate conceptual framework to accomplish either prevention or treatment strategies to tackle pediatric obesity.