Obesity: A Global Systems Disease in Transition – Narrative Review

Obesity has moved from an occasional clinical curiosity to a pandemic that now affects one in eight people on the planet. The World Health Organization estimates that 2.5 billion adults – 43% of the adult population – and nearly 400 million children and adolescents already live with excess weight, with prevalence rates still climbing in every region. A 2025 Lancet synthesis of Global Burden of Disease data warns that, without decisive action, 60% of adults and one-third of children will have overweight or obesity by mid-century. This review gathers evidence from high-indexed journals published between 2023 and 2025 to trace the scale of the epidemic, unpack its multifactorial roots, explain the latest insights into pathophysiology, and evaluate the full spectrum of interventions – from lifestyle coaching to next-generation incretin drugs and supportive fiscal policy.