We have made an extensive study of the development of picky eating behavior in childhood, and its effects on diet and growth, using data from the Avon Longitudinal Study of Parents and Children (ALSPAC). Questions, inspired by experience, were asked at regular intervals about difficulties parents had in feeding their child and how they responded to these difficulties. The data collected have provided insight into the development and consequences of being a picky eater in childhood. The importance of collecting prospective data on diet and feeding behaviors in early life studies is emphasized.