Evidence that early nutrition can influence (program) later cardiovascular health was first obtained for the long-term effects of overfeeding in animals. This concept is now supported in humans by evidence for a beneficial effect of breast-feeding on the major components of the metabolic syndrome (obesity, blood pressure, cholesterol metabolism, and insulin resistance) that affect cardiovascular risk. The size of this effect is large and relevant for public health. The potential mechanisms involved include a benefit of slower weight gain in breast-fed compared with formula-fed babies.