7 Billion Cavemen?

by William Green

Recently by William Green: The Anarchist’s Diet

Grok the caveman gnawed his roots and venison in rhythm with the seasons, with no grain to fatten him and no State to control him. His paleo/primal lifestyle is just the sort of nonconformist, individualistic, thumb-your-nose-at-the-establishment idea that libertarians eat up, and it's hard to argue with the basic premise: our bodies are not evolved for eating bread, but for hunting and gathering. It's also hard to argue with sustained weight loss and increased health and fitness. But after I wrote The Anarchist's Diet, one primal enthusiast emailed this question: "Could a grain-free world sustain 7 billion people?" This is a good question, since Grok's world included, at most, 15 million or so. But I think the primal lifestyle is not only healthy, but ethical and responsible. Here's why.

The potential problem with a shift back to meat and vegetables is pretty clear. Cattle burn roughly 90% of the calories they consume, converting only about 10% of the calories in the plants into meat and fat. That means eating meat is a less efficient use of the sun's energy for feeding people. To simplify a worst case scenario, let's assume that all 7 billion of us eat nothing but grain and require all of the current crop production to survive. If everyone switched to a 100% carnivorous diet, 90% fewer people could be supported, and enormous food shortages and price increases would follow.

This scenario is grossly oversimplified, of course. We are already using about 40% of world grain production for livestock feed, and the primal diet replaces grains not only with meat, but with increased intake of vegetables. And perhaps more importantly, according to USDA data, as much corn is currently being used for fuel as for feed, so switching grain from fuel to feed alone could increase available feed stock by 100%.

And before we go further, we should acknowledge that similar food supply problems have been caused by the production of ethanol and biodiesel, and the same problems would likely be caused by large scale adoption of organic farming practices or the elimination of genetically modified crops. Chemical fertilizers and genetic technologies have increased crop yields by a factor of five since the 1930s, and could not be dispensed with without massive food supply issues. In fact, it seems to me the same problem would be caused if everyone on the planet simply increased their intake of vegetables like lettuce and tomatoes, which have a low calorie content and much less efficient than grains for sustaining 7 billion people.

But why should we consider such worst case scenarios as likely? The grim scenario above assumes stagnant technologies and levels of crop production. Similar pessimistic and simplistic assumptions made both Thomas Malthus and Paul Ehrlich famously and embarrassingly wrong with their predictions of mass starvation and famine. I see no reason why doom and gloom predictions and worst case scenarios should be correct this time. We are not even close to the absolute upper limit on Earth's primary productivity, which is theoretically limited only by solar energy (and perhaps limits on the theoretical efficiency of photosynthesis and available plant nutrients).

Maybe this is why estimates of the maximum population Earth could support have ranged from <1 billion to 1000 billion. The median upper estimate in all of the literature he reviewed was 12 billion. As Joel Cohen wrote, "Such estimates deserve the same profound skepticism as population projections. They depend sensitively on assumptions about future natural constraints and human choices." That is, who can tell what factors will change in the future? Who can tell what innovations humans will come up with to increase food supplies?

And even if 7 billion can't live primally, is that a reason for me to eat grains? How are we to decide such things? The real question is not "Could a grain-free world sustain 7 billion people?," but "Will my abstinence from meat really help others?" Will other people really get more or cheaper food? Will they be healthier and happier? And how do these considerations weigh against my personal benefits and costs.

If everyone in the USA went vegetarian, feed grain would rot in massive storage piles and grain prices would initially plummet (barring government intervention). But what are the chances production levels would stay high? A more likely scenario is that farmers would abandon grains and many would stop farming altogether. Demand for biofuels might increase to make up the difference, but then the prices would be just as high. Either way, it's not as simple as it seems. It's an example of Hazlitt's One Lesson.

And the rotting piles would demonstrate that we don't live in some Nirvana in which surplus food is instantly and efficiently distributed to all those in need. Amartya Sen has argued that famines are primarily political. And when we do send food directly to starving nations, if it ever gets there at all, the effects are often hard to predict, and even damaging to local economies. How much less predictable or effective is a simple reduction in my personal intake of meat?

It seems to me, guilty feelings about taking too big a piece of the pie are caused by sloppy thinking. There is no zero-sum game in food yet, and there may never be. And who knows, a gradual shift away from grain and toward a more natural way of life may be just what this world needs. So when I weigh these nebulous, uncertain, unpredictable, and even unlikely potential negative outcomes of meat eating against the obvious benefits to me and those around me, it seems clear. For now at least, I will choose more health and vitality, and I will hope for and look forward to the day when 7 billion (and counting) can do the same.

November 13, 2012

Bill Green [send him mail] teaches chemistry and biology at a government school and operates a private tutoring service. He writes as the Hartford Libertarian Examiner and at williampgreen.com.

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