Sustainable Office Intervention, Impact of a Sustainable Lifestyle on Diet, Physical Activity and Carbon Footprint

The participants will be recruited at companies in the Swedish office sector, and after recruitment and baseline assessment, the participants will be randomly assigned to one of two groups Healthy Lifestyle (HL) or Sustainable Lifestyle (SL). All participants will complete web-based questionnaires including background information about weight, height, diet, physical activity, smoking, education and other relevant background variables at the beginning of the study as well as at the end of the study. Participants will attend separate group-based workshops 6 times during the 8-week intervention period held by trained personnel. During these workshops, participants will be guided by education, food provision, and assistance to identify facilitators and barriers to a healthy or sustainable lifestyle. In addition, adherence to a healthy or sustainable lifestyle will be reinforced using a behavioral support package provided through a digital platform during the intervention period. We will compare baseline, midpoint, and final (i.e. week 0, 4 and 8) nutrient intake, CO2e, and the dietary sustainability score for the two diets with an ANOVA model. We assume a dropout rate of 10-15% after baseline assessment (based on our previous pilot study from the fall of 2017) Climate Friendly and Ecological Food on Microbiota (CLEAR). Therefore, we will recruit 47 people to each group to have at least 40 at the end of the study. With 40 participants in each group, this analysis has \>90% power to detect a 50% reduction in CO2e for the intervention group. To gain further insight into the development of intake of nutrients, CO2e, and the dietary sustainability score during the follow-up, we will use linear mixed models, with individual-specific baseline trajectories. Moreover, we will perform substitution analyses, i.e. scenarios where a number of meals high in CO2e are substituted for meals low in CO2e. Statistical analyses will be done in R-statistics.