Background The purpose of this study was to describe the workplace environments of young adults and examine associations with diet, physical activity (PA) and body mass index (BMI).

Methods Cross-sectional data were collected (2008–2009) from 1538 employed young adult participants in Project EAT (Eating and Activity among Teens and Young Adults), a diverse population-based sample. Survey measures assessed height, weight, diet, moderate-to-vigorous PA, transportation-related PA and perceptions of the workplace food and PA environments (eg, soda availability, coworker support). Healthful characteristics were summed to reflect overall workplace healthfulness. Modified Poisson regression analyses conducted in 2015 identified associations between workplace food and PA environments and diet, PA and BMI.

Results The healthfulness of workplace environments was suboptimal. Greater exposure to healthful workplace characteristics was related to more young adults engaged in favourable diet and PA behaviours and a lower prevalence obesity. For example, adjusted rates of obesity were 24% and 17% among those reporting low (≤1 characteristic) versus high (≥3 characteristics) exposure to healthful food environments, respectively (p<0.05). Workplace characteristics independently associated with weight-related outcomes included soda availability, proximity to a fast food outlet, living close to work and perceived ease of eating a healthy diet or being active at work.

Conclusions A more healthful workplace environment overall, including physical attributes and perceived social norms, may contribute to more favourable weight-related behaviours and lower prevalence of obesity among young adults. Employer-initiated and community-initiated policies may represent one way to create healthier workplace environments for young adults.