I've developed this crazy formula, based too much on thinking about it and not enough on testing it out, but here it is...

1. Base Calories
Lean Weight x 10 + Fat Weight x 5
e.g. I'm 6'0.5" 210#, lean mass = 150#
Base Calories = 150 x 10 + 60 x 5 = 1800 Cal

2. Hiking Calories
Total Weight x ( Miles + Gain/500')
e.g. 210# + 25# skin out, 10 miles, 2500' Gain
Hiking Calories = 235 x ( 10 + 5 ) = 3525 Cal

3. Gross Calories = Base Calories + Hiking Calories
e.g. 1800 + 3525 = 5325 Calories

4. Gross Macronutrients
Protien = 10% Gross Calories / 4 = 532.5/4 = 132g
Carbs = 40% Gross Calories / 4 = 533g
Fats = 50% Gross Calories / 9 = 2663/9 = 296g

5. Body Fat Burned
Lesser of Body Fat x 50g/# or 80% x Gross Fat Burned
e.g. Lesser of 60# x 50g/# = 300g or 80% x 296g = 237g
Body Fat Burned = 237g

6. Food Weight
Protien = 10% Gross Calories / 4 = 532.5/4 = 132g
Carbs = 40% Gross Calories / 4 = 533g
Fats = Gross Fats - Body Fat = 296g - 237g = 59g
Fibre = Carbs/10% = 53g
Moisture = 10% (Protien+Carbs) = 66g
Total Food Weight = 132+533+59+53+66 = 843/454 = 1.9 pounds
If not losing weight extra fat = 0.4 pounds for 2.3 pounds