The non-GI MRE's, in the clear bags, sold at surplus stores, have about 800 calories, whereas the GI MREs have 1800 or more. In cold weather a hard working teen will need three non-GI MREs per day, while those not doing hard work, might only need two. Non-GI MRE's, are locally assembled by a crew, and if you analyze them, and reverse engineer the process, you can custom make mission essential rations. Long distant backpackers will vacuum pack spare socks and skivvies. The poly tubing, and heat sealers are cheap. For a few $1,000 your group can assemble MREs and custom accessory packets, exceeding the quality of GI, but using OTS local groceries.