In trekking, by foot, horse or water vessels, one should keep in mind of the additional strength and fluids one needs, in a more active environment.
Protein is OK, but for stamina, think carbohydrates.
If carrying whole fruit and dried fruit, use the heavier, more bulky items first. This will cut down on weight and size of your pack as you wear down from exercises. Before your trek, learn about availabilty and quality of drinking water along your trip. You'll need two or three quarts per person a day on an average and more in warmer weather. Stay away from streams and rivers, unless you've boiled the water.