Original author Harry Harrison discusses the film:
In the book, Omni's Screen Flights/Screen Fantasies, edited by Danny Peary, Harry Harrison discusses the mutilation of his novel in the following excerpt:
"As is standard Hollywood practice, the author of the book upon which this film is based was treated shabbily. All the usual tricks were used: a dummy company was set up to disguise the fact that it was really MGM buying the film rights; a contract was drawn up to prevent the author from having any control over the screenplay - and, of course, creative bookkeeping made certain none of the film's profits reached the author....
Although forbidden by contract to make any changes in the script, I nevertheless pointed out a number of inaccuracies and mistakes I discovered....I propagandized everyone in sight, from grips to actors, by giving them copies of the original book. When Charlton Heston got his, he called across the set to the director (Richard Fleischer), 'Hey, Dick, why aren't you using this title instead of the crappy Soylent Green?' The answer, which Fleischer perhaps did not know, was the decision made in high places that my title might be associated with a long-dead TV series named 'Make Room for Daddy.' Moral: When you throw away a good title, you always get a bad one....
The idiotic cannibal-crackers (not in the book) and the 'big' revelation that they are made from corpses will have been twigged by the audience early on. This, and the murder and chase sequences, the 'furniture' girls (not in the book) are not what the film is about - and are completely irrelevant. The film, like the book, shows what the world will be like if we continue in our insane manner to pollute and overpopulate Spaceship Earth. This is the 'message' of film and book. Both of them deliver this message in a manner unique to science fiction: The technique of background-as-foreground....
Am I pleased with the film? I would say fifty percent. The message of the book has been delivered. It was an exciting experience to see a major film produced by a major studio. It was a humbling experience to meet Edward G. Robinson. A great actor and a great human being. He alone knew that he had terminal cancer when he made the film. He must have chosen to make one more film rather than sit quietly at home and await death. He died before the film was released and it is a tribute to the hard-nosed film executives that they did try to cut out the suicide-parlor scene before the film was released. But it is such an integral part of the film that it could not be done."
http://www.tcm.com/tcmdb/title/2061/Soylent-Green/articles.html