Among chronic non-communicable diseases, cardiometabolic diseases and cancer are the most important causes of morbidity and mortality worldwide. Although high BMI and waist circumference, as estimates of total and abdominal fat mass, are now accepted as predictors of the increasing incidence of these diseases, adult height, which also predicts mortality, has been neglected. Interestingly, increasing evidence suggests that height is associated with lower cardiometabolic risk, but higher cancer risk, associations supported by mendelian randomisation studies. Understanding the complex epidemiology, biology, and pathophysiology related to height, and its association with cardiometabolic diseases and cancer, is becoming even more important because average adult height has increased substantially in many countries during recent generations. Among the mechanisms driving the increase in height and linking height with cardiometabolic diseases and cancer are insulin and insulin-like growth factor signalling pathways. These pathways are thought to be activated by overnutrition, especially increased intake of milk, dairy products, and other animal proteins during different stages of child development. Limiting overnutrition during pregnancy, early childhood, and puberty would avoid not only obesity, but also accelerated growth in children-and thus might reduce risk of cancer in adulthood.