A lot of it depends on the amount of physical activity is being expected of you, (the service member). Desk bound REMF’s don’t really need as many calories as soldier or sailor who is doing exhaustive physical work.
As a point of information, C-rations are absolutely delicious when you are starving. I never got to try MRE’s so I can’t give an opinion on them.
I tried them and had them around when I lived in PA....power out for 2-3 days and that’s what we ate, they are really good...
I was ‘blessed’ with the opportunity to be around when C-rats were fazing out and MREs were being tested. The C rations were ok if you could eat them hot and in the dark, because seeing them would take away your appetite. Now the part about eating them hot was the trick. We would dig a deep hole, place the box In the hole, with the appropriate cans almost completely opened, light the box and let it burn down around the cans. When the fire is out the cans are hot. Eat and enjoy, when done, place all trash in hole and refill. The MREs were a long learning curve at first, some were ok, some were awful. The long range patrol rations were the worst, but they were light weight and kept you alive. If you really want to get nostalgic about C rations, I miss the little packs of smokes. We were able to trade them for some amazing things, back in those days, in some remote places that still valued Americal Cigarettes.