Soylent Green is a classic 1973 science fiction movie starring Charlton Heston, Edward G. Robinson and Chuck Connors. It was based on the 1960s science fiction novella about overpopulation by Harry Harrison, Make Room! Make Room! describing a future dystopia of the Malthusian catastrophe that might be awaiting us if humanity does not pursue sustainable development.
Warning: Wikipedia contains spoilers
In the novella, real food is too expensive, and the government dispenses rations of food substances made by the Soylent corporation: Soylent Yellow, Soylent Red, and the newest product, Soylent Green.
The latter apparently includes recycled bodies of people murdered by the government for food. (However, this was not in the original novel: Soylent, as the name suggests was derived from Soya and Lentils. Note also that the original book was set in the year 2000, suggesting that some of the projections may have been askew somewhere.)
Soylent Green is also the name of a progressive rock music band.