Feeding Ourselves Without Eating the Planet

A newly published paper in The Lancet Planetary Health challenges the merits of the EAT-Lancet Planetary Health Diet, a template for how to feed all of us hungry humans well while sustaining a viable planet, too.

 The new paper suggests that the proposed diet would result in select micronutrient deficiencies in populations around the globe, threatening public health. 

Let’s probe this dilemma, because stated bluntly, we do need both adequate sustenance, and a hospitable planet on which to ingest it.

No animal can thrive without a habitat to sustain it. For our kind of animal- Homo sapiens- that habitat is, at this point, nearly all of Earth. We have straddled it- but we cannot abandon it. We must have it, intact, for as long as we aim at any approximation of thriving. We have some hope of being healthy, vital people on a healthy, vital planet- or we have no hope of being healthy, vital people.

Personally, I don’t consider our well-being the only reason to revere the majesty of this planet in its native balance. Sure, I care about people- I have devoted my entire professional life to caring for our kind of animal - but I also marvel at this planet’s greatest treasure, the grandeur, glory, and practical magic of biodiversity. Our failure to be awed by this genuinely awesome parade of life, every day, is arguably the quintessential demonstration of contempt begot by familiarity.

I unapologetically revere the natural systems of our planet for reasons that extend beyond both my skin, and that of my kin, proximal and distal. You may share those motivations, or favor a more self-centered version. Either way, we both live here.

Accordingly, we all have cause to support the goals of the EAT-Lancet Commission to sustain ourselves within the bounds of planetary tolerance; we all have cause to advocate for a Planetary Health Diet.

The authors of this new paper advance a concern that is potentially true, but also rather contrived, and perhaps unfair. They note that adoption of the Planetary Health Diet (PHD), while obtaining foods from local and regional sources that prevail today, would potentially leave millions around the world vulnerable to deficiencies of vitamin B12, iron, calcium, and zinc. This conclusion is based on the idea that diverse populations around the world would adopt the common standards of the PHD, but source that diet with only the foods available to them right now. That combination- global standards, local/regional sourcing- results in potential deficiencies for those with limited access to a diversity of wholesome foods.

Of note, these are "deficiencies" of a theoretical variety, i.e., less than the recommended intake- not deficiencies as defined by actual adverse outcomes (an issue emphasized in correspondence with my friend and colleague, Dr. Walter Willett, an architect of the PHD, who plans to address this issue more fully in a letter to the editor). Further, the authors fail to contrast the potential harms of these potential deficiencies with the potential harms of the dietary alternatives they espouse to avoid them - and suggest which is the likely path of "least net harm."

For the PHD to impose any nutrient deficiencies, actual or theoretical, among the most vulnerable globally, it would first need to be adopted globally. That is a tall order- and we could all benefit from the good people at EAT-Lancet appending “how to” guidance to their “what to” efforts. In other words, they’ve characterized where we are, and where we need to be- but thus far offered less about how to get there from here. We need that- in discrete, actionable steps for a plurality of stakeholders.

If we indulge in the fantasy that we actually could rally the entire world to eat in accord with shared and long-term imperatives, rather than immediate gratification- then what’s good for the fantastic goose should be just as good for the imaginary gander. Globalizing the PHD should be accompanied by globalizing the food supply, so that “nutrition” is equitably distributed. If everyone, everywhere (all at once, and at different times, too) had access to an appropriate diversity of high-quality food options, the “threat” of nutrient deficiency with a diet designed to preserve the planet would dissipate. 

Some of this is already happening- we have a substantially global food trade as is. Needed is an effort to make that global trade equitable, rational, and goal-oriented- rather than inequitable, irrational, with near-term profit the only goal. If we can socialize the PHD to 8 billion of us all around the world, we can choreograph food distribution far better than we do now, too.

We also have recourse to selective, judicious supplementation, and fortification. Public health has long taken advantage of this option routinely before now, with iodine in salt, folate in flour, and vitamin D in dairy as just a few examples. There is no reason not to do so in the service of feeding ourselves well without devouring our planet.

The authors of the recent paper acknowledge this, but only as a rather begrudging aside. For one thing, they present fortification and supplementation as bundled up with ultraprocessed foods and their increasingly recognized ills. But this is excessive lumping by a wide margin; iodine in salt does not an ultraprocessed food make, to highlight just one example.

For another, the authors assert, or at least imply, a greater virtue in achieving comprehensive nutritional adequacy only by means of whole foods than with selective additions of supplements or fortificants.

There is much to be said for the merits of a whole-food, plant-based diet, to be sure; I say it, often, emphatically, and in every medium at my disposal. I eat just such a diet, too- and still benefit both from fortificants in some of my foods, and select supplements (as an example: I get my long-chain omega-3 fats from a daily algae-based supplement so I need not contribute to depletion of the world’s fisheries to do so).

Extending our fantasizing, we might imagine we lived in a world where we have discovered that the food available to us leaves most of us relatively deficient in Vitamin X. In this thought experiment, our job is to devise a sensible means to make Vitamin X sufficiency prevail. Let’s append that we tend to be deficient in Vitamin X even when our diets are otherwise optimal or nearly so in every way.

Let’s also imagine- because it’s inevitably true- that we have the means to synthesize Vitamin X with high efficiency, and either encapsulate it or add it to food as we choose. One option would be to do just that. Another would be to go searching for animals that bioconcentrate Vitamin X, and then devote vast resources to raising vast populations of those animals to be our Vitamin X synthesis machines and delivery system. If we had not yet committed to either- which would be the rational choice?

While it’s true that humans can access vitamin B12 by eating animals, those animals- mostly if not entirely herbivores- get it from its original, bacterial source. A supplement thus merely cuts out the middlecow, middlepig, middlesheep, or middlefish.

As you might be guessing, I refute the intrinsic virtue of raising entire animals to bioconcentrate just several nutrients that we could bioconcentrate on our own behalf at massively lower cost in money, time, effort, environmental impact, cruelty, waste, and the conjoined bioconcentration of various toxins. We might append a bit of reductio ad absurdum to clinch this case. If we follow such “sourcing only from Nature is more virtuous, no matter the costs” logic where it leads, we would not have oxygen tanks, ventimasks, or nasal cannula for patients in respiratory distress- we would simply stuff a fichus up their nose.

The public health threat espoused in the new paper posits that we might effectively globalize not just dietary guidance, but also compliance with it- which serves only the long-term aspiration of saving our planet- while neglecting a concomitant globalization of food distribution, which would serve that favorite of human pastimes: making money now. That we would accomplish the distally virtuous while neglecting the proximally profitable seems to me the very peak of implausibility.

There is one more, timely imperative to consider. The EAT-Lancet effort projects from the current population of 8 billion to 10 billion humans. But the current sum of us has already displaced tremendous biomass from the rest of life to make it our own. Stated bluntly: there are more than enough of us. Efforts to empower women globally, to enable “family planning,” and to stabilize the human population should be among our shared, urgent priorities. In such context, we need to elevate the thinking of economists and policy makers who recognize the calamitous fallacies of “infinite growth” in a world of finite resources.

If we got a grip on the human population; if the global trade in food were rational; and if we favored more efficient means of nutrient bioconcentration than cows - we could feed ourselves optimally without devouring our planet.

Accordingly, I object to the objections in the new paper. I believe we can have our nutritionally adequate planetary health diet, and not eat our planet, too.

Will we do either while there’s much of anything left to save? Ah, there’s the rub.