Materials and methods
Study design
Cross-sectional baseline data were obtained from a large clustered
controlled trial, The Food Choice atWork Study (Geaney et al., 2013a).
It was a study of the effectiveness and cost-effectiveness of complex dietary
interventions that were focused on environmental dietary modifications
alone or in combination with nutrition education in four
multinational manufacturing workplace settings.
Study population
A randomsample of 828 participants aged 18–64 yearswere recruited
fromthe selectedworkplaces (workplace A: 100 (70% response rate),
workplace B: 224 (70% response rate), workplace C: 392 (60% response
rate),workplace D: 112 (91% response rate)). The number of employees
recruited per workplace reflected the difference in company size. The
sample was powered to detect a decrease in BMI by 1 kg/m2 and a 2 g
average fall in dietary salt intake between the control and intervention
groups post-delivery of the interventions. Eligible employees were permanent,
full-timeemployeeswho purchased and consumed at least one
daily meal at work. A wide variety of hot and cold meal options were
available for employees during working hours. Many food options
were served using a buffet-style so employees' managed the frequency
and quantity of their own food items.
Data collection
Participants were asked to complete food frequency questionnaires
(FFQ), nutrition knowledge questionnaires and demographic questionnaires.
Physical assessments were conducted by trained research assistants
as per the Standard Operating Procedures (SOP) manual (Geaney
et al., 2013b). All data were collected during work hours in the individualworkplaces.
Participantswho did not complete all assessmentswere
excluded fromanalysis. No incentives were provided to employees participating
in the study.