I found a study on www.pubmed.gov on a single individual's experience on a 118 day appalachian Trail hike on his blood chemistry and other indexes of health.
He lost weight, lost fat, and greatly improved his blood cholesterol. When will backpacking become covered by health insurance?
Wilderness Environ Med. 2009 Winter;20(4):347-52.
A long-duration (118-day) backpacking trip (2669 km) normalizes lipids without medication: a case study.
Devoe D, Israel RG, Lipsey T, Voyles W.
College of Applied Human Sciences, 214 L.L. Gibbons Building, Colorado State University, Fort Collins, CO 80523-1501, USA. firstname.lastname@example.org
OBJECTIVE: To evaluate the effects of a long-distance backpacking trip on body composition, weight, blood lipids, and lipoproteins. METHODS: Single-subject (male, aged 49 years) study of an experienced backpacker who hiked 118 days on the Appalachian Trail. Outcome measures that were assessed pre-hike and post-hike included body fat (%) by hydrostatic weighing and skinfold assessment, height and weight, body mass index (BMI), circumference measurements (umbilicus, anterior suprailiac, maximum hip, greater trochanter, minimum waist, umbilicus/anterior suprailiac ratio), and blood pressure (systolic and diastolic at rest and peak). Dietary analyses (total kilocalories, protein, carbohydrate, fat, cholesterol, saturated fat, monounsaturated fat, polyunsaturated fat, dietary fiber) were conducted pre-hike, on days 54 through 56, and on days 98 through 100. Blood lipids and lipoproteins (triglycerides, high-density lipoprotein, low-density lipoprotein) were measured pre-hike, on day 89, and post-hike. RESULTS: Pre-post differences showed decreases in body weight, from 85.3 kg to 73.9 kg (-11.4 [-13.4%]); percent body fat, hydrostatic weighing, from 25.18 to 14.31 (-10.87 [-43.2%]); percent body fat, skinfolds (7-site), from 23.79 to 11.61 (12.18 [-51.2%]); and BMI, from 29.37 to 25.46 (-3.91 [-13.3%]). Pre-post differences in blood lipid changes over the course of 118 days were as follows: triglycerides (mg x dL(-1)) fell from 319 to 79 (-240 [-75%]); total cholesterol (mg x dL(-1)) fell from 276 to 196 (-80 [-29%]); high-density lipoprotein (HDL) (mg x dL(-1)) rose from 46 to 63 (+17 [+37%]); low-density lipoprotein (LDL) (mg.dL(-1)) fell from 167 to 118 (-49 [-29%]); LDL/HDL ratio fell from 3.63 to 1.87 (-1.76 [-48%]); and total cholesterol/HDL ratio fell from 6.00 to 3.11 (-2.89 [-48%]). CONCLUSION: The physical activity and diet associated with an extended backpacking adventure can considerably reduce and clinically normalize blood lipids and lipoproteins without medication and can very positively affect body composition and weight.
PMID: 20030443 [PubMed - indexed for MEDLINE]