Total energy intake and self-selected macronutrient distribution during wildland fire suppression

Introduction: Wildland firefighters (WLFF) work long hours in extreme environments resulting in high daily total energy expenditure (TEE). Increasing work shift eating episodes and/or providing rations that promote convenient feeding has shown augmented self-selected work output, as has regular carbohydrate (CHO) consumption. It remains unclear how current WLFF feeding strategies compare to more frequent nutrient delivery. Our study’s aim was to determine WLFFs’ self-selected field total energy intake (TEI), composition, and patterns feeding during wildland fire suppression shifts. Methods: 86 WLFF (16 female, 70 male; 27.5 ± 6.4 yr) deployed to fire incidents across the United States throughout the 2018 fire season. Pre- and post-shift food inventories collected at basecamp provided item-specific nutrient content (calories [kcal], CHO, fat, protein). Work shift consumption (TEI, feeding frequency, episodic composition) was monitored in real-time by field researchers on fireline via observational data capture using mobile tablets. Shift work output was determined via actigraph accelerometry. Results: Work shift length averaged 14.0 ± 1.1 hr, with a TEI of 6.3 ± 2.5 MJ (1494 ± 592 kcal) (51 ± 10, 37 ± 9, 13 ± 4% for CHO, fat, and protein, respectively). WLFF averaged 4.3 ± 1.6 eating episodes (1.4 ± 1.3 MJ [345 ± 306 kcal] and 44 ± 38 g CHO.episode-1). WLFF who consumed \u3e20 kcal.kg-1 averaged less sedentary activity than those consuming \u3c16 kcal.kg-1. Conclusion: The present work shift TEI approximates 33% of previously-determined WLFF TEE and demonstrates that current WLFF consumption patterns may not deliver adequate nutrients for the occupational demands