A pragmatic research design is planned with three linked phases. The first involved the development of an interactive multimedia programme, namely ProActive Assessment of Overweight Risk during Infancy (ProAsk) which includes the IROC and a therapeutic wheel, to facilitate health professionals' discussions with parents/legal guardians/carers about overweight risk and prevention during infancy. This phase is a feasibility study of the ProAsk intervention with parents/legal guardians/carers and health professionals. The study will gather information to inform the trial design and data collection procedures for a Randomised Controlled Trial (RCT) of overweight risk identification and intervention during infancy by UK health visiting teams.