Youth with DS have a high prevalence of overweight and obesity compared to youth without DS. Increased leptin levels, poor nutritional plans, decreased resting energy expenditure, comorbidities and low physical activity levels are determinants of obesity among PWDS. Obesity was confidently linked to dyslipidaemia, obstructive sleep apnea and gait disorder. Interventions for obesity prevention and control included exercise-based programmes, which did not achieve sufficient results. This evidence concerns the gene LEP and obstructive sleep apnea syndrome.