How do ration modern day food to ensure everyone gets a balanced amount of food?
In the 1940s and 1950s people pretty much all cooked from scratch. Since then we have developed the food processing industry. You can't unpick that without risking huge numbers of jobs and completely changing the way we all eat with other catastrophic consequences!
Yes, we SHOULD cook more from scratch, and I generally do cook a lot from basics so I know what I'm eating, but even I use the odd curry sauce etc. The idea that we could reverse all this, is utter fantasy and nonsense. Unless as previous posters have joked, we decide to become North Korea.
A lot also stems from us not knowing how much we should be eating; people think that a standard portion of meat should be at least twice what is actually recommended. Try and buy a steak in a resturant the size which is recommended. You'll struggle. Personally I'd like the option because I'm tiny and the size of portions is far to big for me, but for DH he'd just walk out hungry. He cycles to work and generally needs far higher than the recommended 2500 calories for a man, whereas I need a lot less than the recommended 2000 calories for a woman - I generally needs around 1300 - 1400 calories. Which makes cooking at home a bit of a challenge in itself! But it requires consciously thinking about it and a lot of self control on my part. DH needs the food to pursue a more active lifestyle - which also should be encouraged.
My point being these arbitary calorie numbers are utterly meaningless in 2018. The difference between DH and myself just illustrates it. What works for him doesn't work for me and vice versa. It works marginally better if you are cooking from scratch but its crap and doesn't solve anything when you are talking about rationing preportioned ready meals.
One of the best 'diet plans' which is proved as being pretty effective is simply reducing your plate size to 9 inch plate as it affects the psychology of how much you eat simply by affecting how much you put on your plate to begin with. You'll notice that if you eat out, you'll almost never get a plate this size.
Arguably we should ban the sale of larger plates as standard, instead either having a 9 inch (or smaller) or a much large obviously serving size plate rather than introducing rationing. And even this would have the problem of all the bigger plates already in circulation!
It comes down to people needing to make conscious and educated decisions about how and what they eat. And to take responsibility for it themselves rather than have the state impose meaningless nonsensical rules about it.
One of the biggest inhibitors to introducing rules about advertising the number of calories in meals for restuarants is how chains can afford to work this out but its utterly prohibitive and impossible for independantly owned restuarants particularly ones which might change their menus on a regular basis to reflect seasonality.
Honestly, you'd think that the people proposing these rules lived on a different planet or had no idea whatsoever what they were talking about.