title: Protocol for a pilot randomised controlled trial of an intervention to increase the use of traffic light food labelling in UK shoppers (the FLICC trial).
abstract: BACKGROUND
  Traffic light labelling of foods-a system that incorporates a colour-coded assessment of the level of total fat, saturated fat, sugar and salt on the front of packaged foods-has been recommended by the UK Government and is currently in use or being phased in by many UK manufacturers and retailers. This paper describes a protocol for a pilot randomised controlled trial of an intervention designed to increase the use of traffic light labelling during real-life food purchase decisions.
  
  
  METHODS
  The objectives of this two-arm randomised controlled pilot trial are to assess recruitment, retention and data completion rates, to generate potential effect size estimates to inform sample size calculations for the main trial and to assess the feasibility of conducting such a trial. Participants will be recruited by email from a loyalty card database of a UK supermarket chain. Eligible participants will be over 18 and regular shoppers who frequently purchase ready meals or pizzas. The intervention is informed by a review of previous interventions encouraging the use of nutrition labelling and the broader behaviour change literature. It is designed to impact on mechanisms affecting belief and behavioural intention formation as well as those associated with planning and goal setting and the adoption and maintenance of the behaviour of interest, namely traffic light label use during purchases of ready meals and pizzas. Data will be collected using electronic sales data via supermarket loyalty cards and web-based questionnaires and will be used to estimate the effect of the intervention on the nutrition profile of purchased ready meals and pizzas and the behavioural mechanisms associated with label use. Data collection will take place over 48 weeks. A process evaluation including semi-structured interviews and web analytics will be conducted to assess feasibility of a full trial.
  
  
  CONCLUSIONS
  The design of the pilot trial allows for efficient recruitment and data collection. The intervention could be generalised to a wider population if shown to be feasible in the main trial.
  
  
  BACKGROUND
  ISRCTN: ISRCTN19316955.
authors.affiliation: Nuffield Department of Population Health, British Heart Foundation Centre on Population Approaches for NCD Prevention, University of Oxford, Oxford, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Scarborough
authors.affiliation: Food, Consumer Behaviour and Health Research Centre, University of Surrey, Surrey, UK.
authors.forename: Charo
authors.initials: C
authors.lastname: Hodgkins
authors.affiliation: Food, Consumer Behaviour and Health Research Centre, University of Surrey, Surrey, UK.
authors.forename: Monique M
authors.initials: MM
authors.lastname: Raats
authors.affiliation: Nuffield Department of Population Health, British Heart Foundation Centre on Population Approaches for NCD Prevention, University of Oxford, Oxford, UK.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Harrington
authors.affiliation: Nuffield Department of Population Health, British Heart Foundation Centre on Population Approaches for NCD Prevention, University of Oxford, Oxford, UK.
authors.forename: Gill
authors.initials: G
authors.lastname: Cowburn
authors.affiliation: School of Biological Sciences, Queen's University Belfast, Belfast, UK.
authors.forename: Moira
authors.initials: M
authors.lastname: Dean
authors.affiliation: Nuffield Department of Population Health, British Heart Foundation Centre on Population Approaches for NCD Prevention, University of Oxford, Oxford, UK.
authors.forename: Aiden
authors.initials: A
authors.lastname: Doherty
authors.affiliation: Nuffield Department of Population Health, British Heart Foundation Centre on Population Approaches for NCD Prevention, University of Oxford, Oxford, UK.
authors.forename: Charlie
authors.initials: C
authors.lastname: Foster
authors.affiliation: National Perinatal Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK.
authors.forename: Edmund
authors.initials: E
authors.lastname: Juszczak
authors.affiliation: Nuffield Department of Population Health, British Heart Foundation Centre on Population Approaches for NCD Prevention, University of Oxford, Oxford, UK.
authors.forename: Anne
authors.initials: A
authors.lastname: Matthews
authors.affiliation: Nuffield Department of Population Health, British Heart Foundation Centre on Population Approaches for NCD Prevention, University of Oxford, Oxford, UK.
authors.forename: Anja
authors.initials: A
authors.lastname: Mizdrak
authors.affiliation: National Institute for Health Innovation, University of Auckland, Auckland, New Zealand.
authors.forename: Cliona Ni
authors.initials: CN
authors.lastname: Mhurchu
authors.affiliation: Food, Consumer Behaviour and Health Research Centre, University of Surrey, Surrey, UK.
authors.forename: Richard
authors.initials: R
authors.lastname: Shepherd
authors.affiliation: Food, Consumer Behaviour and Health Research Centre, University of Surrey, Surrey, UK.
authors.forename: Lada
authors.initials: L
authors.lastname: Tiomotijevic
authors.affiliation: Food, Consumer Behaviour and Health Research Centre, University of Surrey, Surrey, UK.
authors.forename: Naomi
authors.initials: N
authors.lastname: Winstone
authors.affiliation: Nuffield Department of Population Health, British Heart Foundation Centre on Population Approaches for NCD Prevention, University of Oxford, Oxford, UK.
authors.forename: Mike
authors.initials: M
authors.lastname: Rayner
keywords: Food; Nutrition; Nutrition labelling; Traffic light labelling; Trial