There are several problems with using a vacuum sealer with backpacking food. First, with dry materials, especially those containing things like noodles and other sharp-cornered items, is that the package will soon spring a leak where the plastic is tightly stretched over a sharp point. Second, vacuum sealed packages form an irregular-shaped, hard mass. Packing these "masses" leaves a lot of air space in your food container. Third, if you vacuum seal anything with grease or oil in it (eg. Fritos, nuts etc.), the grease or oil will migrate through the entire package. Finally, if you try to vacuum seal liquids, they will get sucked into the vacuum sealers plumbing making a major mess. Otherwise, they work just fine.