As an aside, all that white crap you see in the opened tins? Yes, indeed it's fat. One reviewer said it was advertised to be around 20 to 30 percent but it looked more like 40 to 50 percent. I guess when you heat it it turns liquid, so you're supposed to drink it.
And most of the rations now come with a "vitamin tablet" which you ingest once a day, I guess that's to help combat scurvy, and any other vitamin deficiencies found in the rations.
As for the Russian cantonments and their field kitchens...it seems they really haven't changed much since WWII, though I read even during WWII many conscripts didn't even have tinned food, it was typically packed loose in bags and/or scrounged from whatever was available.