Weight Reduction. All fresh foods contain water, which is its main source of weight (fruits are more than 80 to 90% water). However, during drying about 98% of the moisture in the food substance is removed, which reduces the weight by as much as 90%, making it lighter to carry backpacking. Aside from freeze-drying’s use in backpacking and camping, the military also freeze-dries foods to make it easier for one person to carry large amounts.