The most popular growth chart, produced by the US National Center for Health Statistics (NCHS), has been used for nearly 30 years to provide a reference against which to judge the growth of a new baby. Introduced in 1977, when rampant obesity had yet to manifest itself, its main aim was to make sure babies didn't suffer from malnutrition. What is now being increasingly recognised is that these charts were based on babies that were atypically heavy: almost all of them had been bottle-fed and came from white, middle-class families in Ohio.