Not quite anecdotal, but a very narrow range of subjects. Sample of 19, all male, between 19 and 26, medium age 21. Approximately half were smokers. All had sc

Not quite anecdotal, but a very narrow range of subjects. Sample of 19, all male, between 19 and 26, medium age 21. Approximately half were smokers. All had scored a class I or II PFT prior to deployment, had passed a physical, and were in good to excellent health. Environment and Conditions = Aircraft carrier on gonzo station in the Indian Ocean. Period = 4.5 months. Working temperature range 24 to 35C, 50 to 100%RH. IMA mostly sedentary, sitting at avionics bench in air conditioned space. OMA mostly active, on flight deck or on hanger deck Work level = 12 to 24 hr/day for OMA(this includes chow breaks). 10 to 20 hr/day for IMA. Both worked 7 days/week. Food Intake - OMA people ate 3x to 5x per day where range of consumption not less than 3400 cal/day. High end of consumption range indeterminate, probably over 5700 cal/day. IMA people ate 3x/day, unless standing a mid-watch, where range of consumption was 3100 to 4200 cal/day. About 30% of OMA subject did weights 3x to 5x per week. Essentially all IMA lifted 2x to 6x per week. Results - all OMA people lost between 5% and 20% body mass by end of cruise. I lost approx 9%, but may not be representative because I spent approx 30% of time working in IMA. IMA people weight gains ranged from 0% to 10%. Source = Senior Chief Corpsman (paygrade E-8) that was collecting performance data on aviation maintenance personnel for unknown reasons. Based on this small sample, I could conclude that both caloric intake and activity level are among the principle things that effect a weight loss or gain.