I was just reading a Soylent Green article written by Harry Harrison, the author of the novel on which the movie was very loosely based. He claims he was swindled like many authors used to claim, but the makers of the movie did listen to some of his suggestions. For example, he influenced the producer to add that montage at the beginning and the year title in order to establish that the movie takes place in the near future to give the movie’s environmental message a sense of urgency.

BTW, along with the cannibalistic soylent green crackers, other ideas in the film that are not in the book include the “furniture” and the suicide parlour.