Lipid profiles and nutritional dynamics of long-distance hiking: A longitudinal study on the Colorado Trail

Current literature on the metabolic effects of long-distance hiking is limited to case studies with discrepant findings, and no prior studies have examined the role of diet in shaping these outcomes. In this study, we investigated changes in lipid profiles and dietary factors among 12 participants who completed the Colorado Trail. Blood lipid measures [low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol, total cholesterol and triglycerides] were obtained pre- and post-trail after a 12 h fast using the Lysun Blood Lipid Analyzer. Dietary intake was assessed pre- and on-trail using a validated multiple-pass 24 h recall. Student's paired t-tests evaluated metabolic changes, and regression analyses assessed associations between lipid changes and dietary factors. No lipid exhibited a statistically significant change at the α = 0.05 threshold. However, LDL-C decreased by 17 mg/dL (P = 0.066), suggestive of a biologically meaningful reduction, given the small sample size. Among 81 dietary variables, LDL-C reduction was significantly associated with decreased intake of added sugars (P = 0.030) and ultra-processed foods (P = 0.039) and with increased intake of minimally processed foods (P = 0.044), vitamin C (P = 0.048) and vitamin K (P = 0.047) during hiking. These findings suggest that long-distance hiking might be associated with lower LDL-C and that diet quality, particularly food processing level, might be correlated with this trend. This study is the first to link dietary shifts systematically to metabolic outcomes in thru-hiking, providing hypothesis-generating insights into the physiological adaptations to prolonged physical exertion and the potential for dietary modulation of lipid metabolism.