On the one hand, you're not likely going to starve to death in 72 hours... You might die of thirst though, so water is more important in this case than food. Use common sense; what is your environment? If you are in a desert, having a higher ratio of water to food might be better, as you probably won't come across many natural sources.

If you're in a location where you are working hard, and water is easily found nearby, you can have a higher ratio of food to water in order to keep up your energy. Same with extreme cold/snow.

Food is important for energy and morale. Most 1st world country inhabitants haven't gone longer than 12 hours without food, much less 3 days, so it would be a major shock to the system <img src="/images/graemlins/wink.gif" alt="" />

I mainly use MREs, but I'd like to get some Air Force GP-1 rations for hiking, and some MRE's for my 72 hour kits. Unfortunately, the only place I can find the GP-1's are on ebay and I don't have an account there. I don't know anything about the commercial rations like mainstay, mayday, SOS bars, other than that they taste horrible. I guess a good side effect is that you won't snack on them, so they'll be around in case of an emergency!

I'm not an expert so take it for what it's worth