Is Corn the Soylent Green of the Future?

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!”?

Eating Less Meat, May Not Help You To Live Forever…But It’ll Sure Feel Like It

I know Harvard researchers are smart, I really do. Yet I have to question the latest study reporting that eating red meat is associated with premature death. Published in the Archives of Internal Medicine, the paper analyzed the relationship between mortality and red meat consumption in a total of 121,342 healthcare professionals and concluded that:

Greater consumption of unprocessed and processed red meats is associated with higher mortality risk… replacement of red meat with alternative healthy dietary components may lower the mortality risk.

As a researcher, I know full well that it’s almost impossible to prove a cause-effect relationship. This is particularly difficult in human studies where other dietary and lifestyle factors have to be accounted for. After all, if you have ketchup on your steak, does the lycopene prevent against prostate cancer? “Associated with” is therefore absolutely the correct terminology for the paper’s authors to use. Alas, in the minds of so many, “associated with” translates to “causes” (especially when it’s a bad news story), and everybody panics accordingly.

The results of this report need to be put into context with our other lifestyle choices. If, as reported, eating unprocessed or processed red meat increases the relative risk of mortality by 13% and 20% respectively, how does that compare to all our other daily activities – driving a car, drinking a glass of wine or eating a candy bar? How do we weigh the risk of consuming a steak or slice of pepperoni pizza against the bottle of Mountain Dew or unwashed raw carrot? After all, during the BSE crisis in the UK, data suggested that the risk of dying from falling out of bed and suffering a fatal head injury was far greater than that from contracting vCJD, yet there was immense consumer concern relating to the perceived dangers of beef consumption.

Relative risk is not a measure that many people understand. Within this study, the absolute mortality risks (i.e. the probability of any one person dying) paint a rather different picture. Out of every 100 men, 1.23 men consuming three servings of unprocessed meat (the equivalent of one 9-oz steak) per week were likely to die, versus 1.30 men eating 6 oz of processed meat (bacon, sausage etc) per day (42 oz per week). Given the small difference in those mortality risks (which were similar for women) yet the huge difference (9 oz vs. 42 oz) in weekly meat consumption, we would be better served by focusing more on other factors (bodyweight, exercise, genetic propensity to specific diseases) that contribute the vast majority of our absolute mortality risk rather than assuming that we can live forever if we only replace a hamburger with a vegetarian meatloaf.

Since this study hit the headlines my Facebook newsfeed predictably been over-run by anecdotes about grandparents who lived to the ripe of age of 101 years while eating bacon and eggs for breakfast, corned-beef hash for lunch and three pork chops (with extra heavy cream in the whipped potatoes) for dinner. Without wishing to be flippant, the one certainty in this life is that we’ll all die at some point – if I restricted my meat intake to the suggested 3 oz per day (or less) I have a sneaking feeling that I might not live forever, but it’d sure feel like it.