MyProtein's MRP
long and short chain protein fractions, low gi carb's and healthy fats, meal in a bag!

especially if he's walking that much, he needs carbs more than he does protein to sustain his energy levels, if he runs out of carbs, his body will start cannibilising muscle tissue for energy before fat stores.... hence why starving yourself n exercising doesnt work and long distance athletes eat 000's of cals of carbs before a race....