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The Math of Soylent Green

The Math of Soylent Green Posted on July 15, 2022

Warning:  Some course language, robust cynicism, and a subject that can be disturbing if you think too hard on it.  Parental discretion is advised.

Back in the 70s, there seemed to be two types of movies that were pretty popular; the characters either lived through a disaster or live in a dystopian society.   The Airport series (Airport, Airport 75, Airport 77), The Towering Inferno, Earthquake, The Poseidon Adventure, and Meteor are just some of the disaster movies.   Those Airport movies were really popular. 

If you wanted things a little more dystopian where events of the world went sideways and everyone either dies or gets left holding the shit end of the stick, you could try out The Omega Man, Logan’s Run, Rollerball, Mad Max, The Planet of the Apes series of movies and, of course, as the subject of this essay would have you intuit, Soylent Green.   It also seems as though Charleton Heston, an arguably two-dimensional person, and pretty terrible actor, starred in a lot of these in both genres.  Whether he had a penchant for acting in disaster movies or just happened to be the hot box office property back then is immaterial.  He pops up in several of those mentioned above.

2022 is the fictitious year in which 1973’s Soylent Green is set and in 2022 all of the movies of its ilk look exceedingly outdated with marginal acting at best.   But the premises they hinged on are still themes in today’s movies and better special effects can further drive home the cautionary messages these movies are trying to make (unless you’re watching a Michael Bay movie in which case it’s just explosions…no social commentary there.)  Plus, they can still be used for thought experiments among friends. 


Soylent Green takes place in a society where food supplies have become scarce due to the ruination of crops and the unsustainability of the food supply for the current world population.  As a result of corporate greed and power-hungry leaders, someone came up with the brilliant idea to use the deceased as food.  In the movie, it’s to feed the poor, but for this thought experiment, I’m going to go with food for the entire populace.  Not a pleasant thought.  That was the whole hook of the movie and the stomach-churning reveal when Charlton Heston discovers it.  He is ultimately carted off on a stretcher after a cringe-worthy fight scene saying, “Soylent Green is people” and one would hope that “The Council” would get wind of this and hold the Soylent Corporation to account.  The camera zooms in on his bloody hand and freezes, subsequently flashing on verdant pastures, waterfalls, rolling plains, and other pastoral scenes in contrast to the dull, gray, monotone feel of the rest of the movie.   It’s hard to say what that all meant.  If nothing else, the movie is a social commentary on how corporate greed and overpopulation can get out of hand and potentially destroy the world. 

But this is not a movie review, is it?  It’s a thought experiment to answer the question: Could this work?

Let’s follow it and see where it leads us.  What if the global food supply suddenly went tits up and there wasn’t anywhere near enough food to feed the entire 7.75 billion people roaming around out there.  Beyond Meat, Inc. (a disturbing name in this context) has morphed into the Soylent Corporation and most of the food out there is little, square, multi-colored biscuits.

The short answer to the question of whether it would be possible is, no way.  Because as thoroughly as the food industry is regulated, there’s no way anything with a key ingredient of “human” would get by the inspectors (even if the meat industry does get away with a lot of questionable stuff.)  Add to that the fact that humans are pretty disgusting animals and making sure that all the microbes and pathogens that live in and on us were not making their way through the processing chain would require herculean effort.    You’d still probably have to cook whatever the end product was into charcoal…just to be sure.  But that’s just me the misanthrope so maybe I’m being too skeptical of the nutritional value of people.

OK, so we’re dead in the water but what if, by some palm-greasing, blackmail-induced, greed-saturated, typically-politician turn of fate, everything worked out and the little green biscuits from the Soylent Corporation got made and were being offered up for food (Tuesday is Soylent Green Day!)  Would the math work out?  Let’s see, shall we?

The average body mass of a human, globally, is 136 pounds1.  On a side note, if you take just North America, which happens to encompass the fattest nation in the world, that climbs by almost 42 pounds2 (fun fact: North America has only 6 percent of the population worldwide but the percentage of global “biomass” is 34 percent3.  We here in ‘Merica are a bunch of fat fucks.) 

Moving on…

There are, roughly, 7.75 billion people in the world.

So, we have some numbers, but it gets complicated pretty fast when we try to calculate the average caloric intake of any given person.   It’s hard to gauge really what constitutes food and who’s eating it.  From a study in Cambridgeshire, England, we learn the average amount of food consumed (not including liquids) is 2.82 pounds4.   But that’s a limited study population.  As another example, what if you were eating just Wheat Thins?  You’d have to eat 10 pounds of apples to get the same caloric value in 1 pound of Wheat Thins5.  Someone in an impoverished village isn’t going to be eating nearly the same amount as someone in a study of villagers in Cambridgeshire, England, or the person who eats only Wheat Thins (scurvy would kill them off anyway so maybe the Wheat Thin addict doesn’t count.  But they would become Soylent Green, wouldn’t they?)  

Let’s uncomplicate things.  Since we’re talking about sustenance derived from meat, let’s go with chicken as the exemplar.  And let’s also pretend, since this is derived from the make-believe of a movie, that everyone eats about the same in this new society.   When it comes to food in the 2022 dystopian society of earth in Soylent Green,  everyone’s equal and all people of the era are eating a balanced diet of Soylent products and getting the Recommended Daily Allowance of calories.  Three pounds of chicken contains the full RDA caloric yield we need6.  And one final assumption we’ll make is that Soylent Green has the same caloric density as chicken.

I have to pause here and mention that there are other Soylent products available.  Namely, Soylents Yellow, Blue, and Red, and there might be other colors as well.   But let’s say all four colors are part of a balanced meal with Soylent Green being the protein component and the others being the side dishes.   That makes it easy and with the maths, easier is better.

Let’s crunch some numbers.   If we’re needing about 2,000 calories a day, with Soylent Green being, say, 60% of those calories, we need about two pounds of it.  We would need to eat 365 x 2 pounds of Soylent Green per year, or 730 pounds. 

But that begs the question, how calorically dense are…erm…”us”.   Unfortunately, we’re not.   If you only factor in the nutritional parts of a person of average weight and build, the yield would be around 75 pounds of edible meat7.  And the possible George Constanzas of the world notwithstanding, everyone must be of average build because there aren’t the 3,400 calories per person (at least in the US) available anymore (I don’t remember where I got that statistic so don’t have a reference, but I did read it somewhere.)  Taking into account the one fact that the ready-for-the-grill weight of a pig is nearly twice that, at 140 pounds8, the total yield of each of us is meager.

Crunching more numbers, to get 730 pounds per year of Soylent Green in your diet, the number of…um…individuals…needed per person per year would be about 9.7 (730 / 75) or 0.027 per day (9.7 / 365).

There are 385,000 new babies per day worldwide9 which would add to the population every day.  We have to account for that.  Moreover, there are 166,279 deaths each day10.  So, we’ll account for that too.

So there we go.  We have some numbers needed to see how long we’ll last.   There is any number of factors not taken into account here.  This is just back-of-the-napkin, entertainment, thought experiment thinking, not Social Sciences 101 and especially not Statistics 101.  So, if you’re going to get on your horse and call out any flaws in this math or logic, just go ahead and ride off in another direction.    

Presumably, with those numbers, we can figure out the progression and what would happen over time.   It’s silly to do the recursive calculation by hand. We have Python, and with that I built a small simulation to see where we’d end up. 

My hypothesis was we’d run out of food in about a year.   But then I realized, that as the population dwindles, less of “us” will be needed to feed the masses.  There is a break-even point when the supply meets the demand and we become self-sustaining.  But there are (at least) two problems with that. Before I get to what those issues are, let’s look at a visual.

At first, I just ran with it and figured out when the population would equal the consumption.   That ended up being about two years (738 days) with the population leveling out at 8.3 million.

Do you see the first problem?   Do you see that orange line labeled Babies in the legend?   It turns out that over that two years, babies far outnumber the population when the supply equals the demand.  The oldest of them is two so a) who’s taking care of all these babies and, b) if there are that many babies, are people dying at pace, or has the Soylent Corporation resorted to murder to keep up with demand?  

And that’s the second problem.   There’s no way babies would continue to be born at the same rate.   In the beginning, the total number of babies represents about .005 percent of the population and that’s important because as the population goes down, so will the total number of babies born every day (we’ll not get into the whole poor nutrition, gestational complications in a dystopian society, pollution, etc. thing.)   

So I added that in as a factor of .00005 x newpopulation to get the babies for each day taking into account the population reduction.

The number of days is reduced significantly and by day 268 the entire population is babies so we have nine-month-olds running the factories and every other aspect of the world since that’s the oldest the babies first born when the simulation started would be. That’s just unrealistic!

So let’s say that we can’t have any more than one baby per person.  We would have to first subtract the total number of babies from the population and then figure out if the number of babies was greater than or equal to that.  

But there’s another factor. If the population is dwindling, presumably the mortality rate would dwindle as well. We’re building up the population with a bunch of healthy newborns and the older folks would likely be the ones to go more often so the numbers of those at death’s door are dwindling. There’s probably some calculus involved there for age groups, risk factors, whatever, but I’m not getting into that. This isn’t about math, it’s about greed, the future of the human race, and how bad an actor Charlton Heston was. Regardless, the graphs above don’t take a dwindling mortality rate into account. Therefore, if we add a factor of .0000215 (166,279 / 7.75 billion) as a multiplier to get the number of deaths each day, that should help fine tune our simulation a little.

Once we factor all that in, we then terminate the simulation at that mythical “break-even point”.  Here’s where we end up.

The final numbers tell the tale:

Days: 211
Population: 29,105,355
No of “Adults”: 14,397,292
No of Babies: 14,708,063
Consumed per day: 807,022

A few more babies than “adults” but perhaps there are people out there who want a bigger family. As the population gets heathier due to more available resources, less pollution, less douchebaggery because we’re all busy taking care of those babies, etc. the mortality rate will adjust accordingly…again, not about math. I’ll leave all those variables to the mathematicians. A “fun” thought experiment can only go so far before it gets boring and stodgy.

Thus, what we find in this sick and twisted simulation is a world where there are as many babies as there are adults.  Someone who wanted to take it further would need to account for the fact that it takes nine months for a baby to mature to birth, on average, and it’s pretty certain the remaining population would not be able to sustain that kind of production. So what happens. Does it become a utopian society where we all become caregivers and our hearts swell with delight at all the babies around? Probably not. We’re human. And humans are dicks.

In the end, what would probably happen is the babies would inherit the earth which means a bunch of babies would run the government and everything else.

So, in that respect, Soylent Green might be accurate since that’s pretty much where we are now.

Golden, 2022

Photo by David Clode

[1] The Weight of the World:  Researchers Weigh Human Population
[2] ibid
[3] ibid
[4] The diet of individuals: a study of a randomly-chosen cross-section of British adults in a Cambridgeshire village
[5] Matthew Kornfield answer to How many pounds of food does the average person eat each day?
[6] Caloric Content in 3 lbs of Chicken
[7] Ever Wonder How Many Calories There Are in…You?
[8] Ibid