I recently had the pleasure of watching the 1973 movie Soylent Green starring Charlton Heston. I won’t spoil the ending for those who havent seen it, but the overarching premise of a big company controlling the food supply to an hungry, overcrowded future population strongly resembles some of the current claims made by the more vehement foodies. The anti-animal-agriculture activists appear to have a similar agenda – if only food production was “sustainable” (a word with a million definitions) without any of those “factory farms (that) pose a serious threat to health” and red meats that “have been linked to obesity, diabetes, cardiovascular disease, and certain types of cancer“, life would be much sweeter.

So what’s the answer? It’s very simple. All that animal feed could simply be fed to humans. According to Pimentel at Cornell University, 800 million people could be fed with the grain that livestock eat in the USA each year. If we ignore the fact that field corn (fed to livestock) is not the same as sweet corn (the corn on the cob that we eat), and assume that field corn could easily be processed into a human foodstuff, Pimentel is right.

Given the average human nutrient requirement (2,000 kCal/day) and the energy yield of an acre of shelled corn (14.5 million kCal), one acre of corn (at 2011 US yields) could supply 20 people with their energy needs (see table below). On a global basis, we currently harvest around 393.5 million acres of corn, therefore we could supply the entire current global population (7.003 billion) using only 90% of the global corn area. Of course that’s assuming zero waste and US crop yields. If we use a more realistic scenario with global corn yields (85 bushels/acre) and 30% food wastage, we can only feed 12 people per acre and would need to increase current corn acreage by 121% to produce enough food to supply the current population. So what happens by the year 2050 when the population is predicted to reach 9.5 billion people? Assuming that we continue to see increases in yield proportional to those over the past 30 years (30% increase in US yields since 1982), that yield increases are exhibited globally, and that we can cut food waste to 10%, we could feed 15 people per acre and we’ll need to increase corn acreage by 79% to provide sufficient corn to feed the global population.

If our dietary requirements can be met by corn alone, the increase in land use won’t be an issue – land currently devoted to soy, peanuts or wheat can be converted to corn. Yet this simplistic argument for vegetarian/veganism suffers from three major flaws. Firstly, it assumes that the global population would be willing to forgo lower-yielding vegetable crops that add variety to the diet – where are the artichokes, kale or radishes in this dietary utopia?

Secondly, as noted by Simon Fairlie in his excellent book, converting to a vegan monoculture would significantly increase the reliance on chemical fertilizers and fossil fuels due to a lack of animal manures. Given current concern over dwindling natural resources, this is an inherently unsustainable proposition.

Finally, corn is currently vilified by many food pundits. The suggestion that our food supply is controlled by corporations who force monoculture corn upon hapless farmers who are then faced with the choice of complying with big ag or being forced out of business are the purview of food pundits (e.g. Michael Pollan and Joel Salatin) and documentaries such as Food Inc. and King Corn. Not a week goes by without another Mommy blogger or journalist publishing an article on the dangers of high-fructose corn syrup, often concluding that if only this ingredient was removed from our food supply, childhood obesity and pediatric type II diabetes would cease to be an issue for little Johnny and Janie pre-schoolers of the future.

It’s frighteningly easy to visualise the Soylent Green-esque vegan future, whereby food is doled out in pre-measured quantities according to dietary requirements – yet what happens when the whistle-blower of 2050 proclaims “it’s made from CORN!”?