2.2. Study Design
SECONDARY, BLIND
A single-site (two arm) RCT was implemented between October 2017 and July 2019. Eligible participants were randomly assigned to intervention or control group directly following the collection of baseline research measurements. Randomisation to the tailored habit-based dietary intervention (intervention group) or minimal/educational intervention (control group) was coordinated by an independent statistician. The allocation sequence to intervention or control group was developed using a block randomisation approach stratified by gender (blocks size = 4) with computer-generated random numbers. Due to the nature of this study and the limited number of research staff, it was not possible to blind the participants or researchers to group allocation. The researchers were unaware of the randomisation schedule until after the baseline assessments when the sealed envelope containing the allocation outcome was opened. All participants were followed up at six weeks, four months and eight months after randomisation for assessment of primary and secondary outcomes. Study visits including assessments and intervention delivery were conducted either at the Centre of Dentistry, Queen’s University Belfast or in the homes of participants, if preferred. The control group was provided with publicly available written information containing current dietary advice at baseline (i.e., UK EatWell Guide leaflet) [The intervention group received the tailored, habit-based dietary intervention, as well as a copy of the UK EatWell Guide (discussed in the same manner as the control group) [A booklet was provided to participants and discussed at the first intervention appointment. The booklet included an introduction on how to create 