Not great for diabetics but beans, rice and corn together will give you a complete protein that none of them has by itself. If you don't eat meat you have to make sure to get "the whole protein package" from a variety of foods. A lot of vegetarians don't get it right and are really unhealthy. Nothing a cheeseburger couldn't help, but "cheese used to have a face", or whatever their reasoning is.
I have a 72 hour freeze-dried food package that's guaranteed to be good for 25 years. After that it will still be edible but will have less and less vitamin content as time goes by. MREs are only good for 10 years IIRC, maybe 20 if stored in ideal conditions but that never happens. That's from the original packing date anyway, and not when you buy them which may be years later if they're real MREs that were sold as surplus. IIRC I bought some that were about 2 years old. And military MREs are sometimes unpacked, examined, and repacked so they'll have more than one date on the case. And they may not all originally be from the same case. The "civilian MREs" I recently read about were really bad. Besides the too small portions, a case with 12 meals has UP TO so many varieties in it, 4 I think. Some people were getting one of one meal, 2 of another and 9 of another, or something like that. I think one guy said his variety was only 2 kinds of meals. Other people if they were lucky got 3 kinds of chili plus sloppy joes or beef barbecue. Real MREs have 12 different meals in a case. If there's one meal in there you really hate, you'll only have one of them, not a half-dozen or so.
Some people refer to MREs as Meal Refusing to Exit and such. I never lived on them long enough to know if they cause constipation or not. I ate C-Rations, MCIs actually but everyone called them C-Rations, and MREs in the army. I don't know how high the calorie content is but one MRE should be enough to live on for a whole day unless you're burning more calories than usual. Sometimes we ate MREs for lunch for 6 weeks at a time, plus ate breakfast and dinner. We weren't working extremely hard in the field but no one got fat eating them. If you ate them for 2 or 3 meals a day they could very well plug you up, I don't know, but one out of 3 meals a day was okay as long as you drank some water now and then. If I drank half a cup of water a day like my mom instead of half a case of bottled water, I don't think I'd $h!t for a week whether I was eating MREs or not. I was in the army before MREs had ration heaters in them so if you were walking around with your MREs for lunch in the winter, you wouldn't want to put them in the cargo pockets of your BDU pants where there fit really well. You were better off putting them inside your coat or your shirt for your body heat to keep them warm. You can eat them cold but body temperature is better than cold, and hot is better yet. After I got out of the army I bought a couple of cases of them for quick, easy meals when camping, but most of the time a can of chili, beef stew, or soup was just fine. All I had to do was heat it on a folding stove with a heat tab. And it's a lot easier to cook it in a pot or canteen cup than it is to cook it in the can.
MCIs, not C-Rations. -->
https://en.wikipedia.org/wiki/Meal,_Combat,_Individual_ration