From a 1973 perspective, when Soylent Green was made, this movie imagines the world in 2022, where the temperature is stifling owing to the greenhouse effect, eventually to be called global warming, and presently climate change.  Overpopulation has reached critical proportions, there being forty million people in New York City alone, most of whom are in filthy rags, sleeping in the street.  Only the very rich and well-connected eat what for us is ordinary food, while the vast majority must eat crackers of different colors indicating their quality, with green being the most desirable because it is the most nutritious.  Even water is rationed.  And electric power is unreliable.

Detective Thorn (Charlton Heston) shares an apartment with his assistant Sol (Edward G. Robinson), referred to as a “book,” on account of his ability to do research on old written material.  We see Thorn having to struggle to use the steps to their apartment because there are so many people sleeping on the stairs.  Later, when a riot starts because there is a shortage of Soylent Green wafers, we see dump trucks called “scoops” being used to remove people from the streets.

Sol helps Thorn investigate murders.  One murder in particular is that of Simonson (Joseph Cotton), one of the privileged few referred to above, living as he does in a luxury apartment.  We witness the murder, in which Simonson is resigned to his fate, even suggesting that he deserves it, that it is in accordance with the will of God.

Before the murder, we saw that Simonson lived with a woman named Shirl (Leigh Taylor-Young), referred to as “furniture,” essentially a prostitute who comes with the apartment.  Thorn checks Shirl for bruises, to see if Simonson used to knock her around.  When he doesn’t find any bruises, he tells her she was a lucky girl.  We see other women being beaten in this movie as well.

When Thorn investigates the crime scenes of rich victims, he typically loots the place, but this time he really scores, taking items of food like beef, vegetables, and liquor.  He also helps himself to the “furniture,” having sex with Shirl without caring whether she wants to or not.  Of course, it’s Charlton Heston, so naturally she likes it. However, we find that the new tenant that will soon be moving into that apartment is repulsive, telling Shirl that he will be having friends come over, and he expects her to be “fun.”  Gulp.

Thorn figures out that Simonson was assassinated, and when he gets too close to the truth, political pressure is applied to get him to end the investigation.  When that doesn’t work, he almost is assassinated himself.

Thorn brings some reference books from Simonson’s apartment for Sol to look into.  From them he learns that Simonson was on the board of Soylent Corporation.  He also learns a terrible secret, the one that led to Simonson’s murder, and he decides to end it all by going to an assisted-suicide center, where he gets to look at scenes of nature as it once was and listen to beautiful music for twenty minutes before dying from some concoction he imbibed.  Just before he dies, he tells Thorn that the plankton used to make Soylent Green is disappearing from the oceans.  As a substitute for the loss of plankton, people that die are secretly processed and turned into the Soylent Green wafers.

For the purpose of this movie, we need to set aside the fact that cannibalism can lead to the transmission of abnormal prions, causing serious neurological disease.  The movie gives no indication of any awareness of this, and audiences watching this movie at the time were doubtless unaware of it as well.  Within this movie, the entire of objection to Soylent Green wafers being made out of people is that the idea is icky.

If disease is not a consideration, then in a world that is overpopulated and in which there is a food shortage, turning people into food is rational.  After all, we are not talking about the kind of cannibalism where we have a bunch of savages standing around a pot with a missionary in it.  The people being turned into food either died naturally or, in the case of assisted suicide, voluntarily.  So, the worst you can say about this form of cannibalism is that the idea of eating people makes us feel queasy.

Neither Simonson’s acquiescence in his own murder nor Sol’s suicide would seem to be warranted, if that’s all there is to it.  However, I have heard of people dying of starvation, even though surrounded by food, when that food is regarded as unpalatable.  For example, I guess one could survive on a cockroach diet, but it would not be easy to pick one up and stick it in your mouth.  On the other hand, if the cockroaches were used to make wafers, then with the proper seasoning they might suffice, especially if the government lied and said they were made out of grasshoppers.

Therefore, in an apparent effort to make this form of cannibalism insidious instead of just repulsive, the scriptwriters have Thorn tell his supervisor, “They’re making our food out of people.  Next thing, they’ll be breeding us like cattle.” Unfortunately, this line, which is supposed to make us even more horrified by what is going on, only makes us groan at its absurdity.

In a world where there are too many people, it makes no sense to breed more.  You just eat the ones you have.

Furthermore, why breed people like cattle instead of just continuing to breed cattle?  Thorn took some beef from Simonson’s apartment, and there is reference in the movie to farms, where cattle are raised.  Why divert resources from cattle breeding in order to breed people instead?

Finally, you would have to feed people more protein to raise them than you would get out of them once you brought them to slaughter.  To put it differently, any person being bred as food would have to be fed the equivalent of several other people over his lifetime.

Because this idea of breeding people is illogical, throwing it in at the last minute undermines this pessimistic vision of the future.