Background: The industrial revolution dramatically altered nutrient availability and physical activity in humans. We recently reported health benefits during an Alaska backcountry expeditionary hunting (ABEH) immersion in four males. The present study extended this work into a larger cohort, included females and evaluated macronutrient intake and blood lipids.
Methods: Seven men (age: 44±6 year, BMI: 27±1 kg/m2) and three women (age: 46±11 year, BMI: 25±3) were recruited. Dietary recall was utilized to macronutrient and energy intake, and the doubly labeled water method was used to determine energy expenditure. During pre- and post-ABEH visits, body composition was measured using dual energy x-ray absorptiometry, intrahepatic lipid (IHL) and muscle cross sectional area (XT) was determined using magnetic resonance imaging/spectroscopy (MRI/MRS) and blood lipids were measured by LabCorp. T-tests were used for statistical analysis, data reported as mean±SD and considered significant at P<0.05.
Results: Total energy intake was 10.4±1.0 MJ/day and energy expenditure was 16.2±3.0 MJ/day, resulting in a negative energy balance of -5.8 MJ/day. Protein, fat and carbohydrate intake averaged 83±31, 83±37, and 235±75 grams/day, respectively. Body weight (Δ-1.2±1.3 kg), BMI (Δ-0.4±0.4 kg/m2), fat mass (Δ-2.5±0.4 kg), visceral fat mass (Δ-0.2±0.1 kg) and IHL(Δ-0.3±0.3 % water peak) were significantly reduced. There were no changes in lean tissue mass (+0.3±1.1 kg) or XT in the upper leg (Δ-0.8±3.3 cm2). Total cholesterol (Δ-34±34 mg/dl), LDL-cholesterol (Δ-24±12 mg/dl), VLDL-cholesterol (Δ-8±7 mg/dl) and triglycerides (Δ-41±35 mg/dl) decreased.
Conclusions. The short-term unscripted ABEH immersion promoted comprehensive benefits in metabolic health that may exceed more modern lifestyle interventions.