The subject of eating is surrounded by a host of philosophical and ethical questions. Together with exercise and psychological factors, diet is unarguably important as a primary determinant of performance, well-being and health. The purpose of this session is to explore some of these issues together.
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There are two broad angles to the question which I want to discuss. Firstly, there is the question of what is good for our bodies, a question to which we do not have a definitive answer and which therefore raises a problem of cultural bias and decision making under uncertainty. The second question is ethical, or esthetic, and very broad, encompassing our role in the food economy and our relationship to nature.
Both of these topics can be illuminated by some historical background.
Although the capacities bequeathed to us by evolution cannot be straightforwardly deduced from the conditions which appear to have governed early human life – as is often forgotten – this remains a useful approach to illuminate many behavioral and biological facts which would otherwise remain obscure. We all know that human beings evolved as hunter-gatherers, initially in the African rainforest, and then in the surrounding savannah (map). The ancestral homeland would have been rich in year-round ready-to-eat food sources, but as demographic pressures pushed humans to expand into adjacent areas, it is likely that pastoralism and agriculture were developed as a way to supplement fluctuating food resources.
The labor-intensity of pastoral and agricultural ways of life would have meant that they came to dominate food supply only when other sources were scarce. Nevertheless, the history of agriculture is coextensive with the history of humanity’s peopling the globe. Jared Diamond’s not uncontroversial theories set out in Guns, Germs and Steel see natural local endowments of crops and domesticable animals as having driven world history in antiquity and explaining today’s economic geography. An amusing look at humanity’s development of agriculture is contained in the following video (the first, by the way, of an excellent series covering significant historical events to quickly get up to speed on anything).
This sort of evolutionary perspective underlies the contemporary Paleo movement and its ideas on diet, which prescribe a preponderance of fish, meat and eggs as protein sources, together with vegetables, fruit, fungi, roots, and nuts, and excluding grains, legumes, dairy products and refined and processed products including sugar. The high proportion of people suffering today from some form of gluten, dairy and other intolerances or allergies might seem to lend some weight to this view. However, there has been plenty of criticism of the Paleo perspective, both in terms of whether it does indeed reflect ancestral diet and in terms of the extent to which this is anyway relevant given adaptations which have occurred since then and spread quickly in the population, such as lactase persistence. Given human genetic and epigenetic diversity, optimal diet may, in fact, require an understanding of individual characteristics, a prospect which the banalization of genetic mapping technology may be bringing ever closer.
The history of agriculture is the history of human demographics, but also of environmental depletion and of the development of hierarchical social norms, including property rights, patriarchy and slavery. Whilst initially agriculture would have sufficed only for subsistence, at some point desire seems to have gotten the upper hand – including as a result of what seem to be some “bugs” in our genetic wiring. The history of sugar is a good example: the tremendous increase in dietary use of sugar in the 18th century (by a factor of 5 in the UK between 1710 and 1770) underlies a good part of the slave trade, but probably offered no nutritional advantage. Given that only honey and ripe fruit were available as sources of sugar to ancestral populations, this popularity is also, to this day, biologically unexplained. Sugar was an important factor behind European colonial expansion. Since its migration from its Indonesian homeland, its use has continued to grow almost everywhere, with only Japan bucking the trend, even though refined sugar is, for most people, almost certainly the single most important dietary contributor to illness, especially as occupations become more and more sedentary.
An abolitionist might therefore have avoided sugar on both health and ethical grounds. But sometimes there is a trade-off: some foodstuffs may be nutritionally desirable, yet their ecological footprint from production to plate may, for some, outweigh these nutritional considerations. Indeed, the very concept of a global agricultural supply chain implies an alienation from our natural environment, long looked to as a source of spiritual values, an alienation which is relatively recent and seemingly continues to accelerate. Ancestral belief systems were inimical to industrial exploitation of the land, and their erosion removes one of the last barriers to the systemic collapse known to economists as the tragedy of the commons. Almost all of us probably hold misgivings concerning animal exploitation, the emotional roots of which stretch back into the antiquity of our species. For early religions and belief systems, the taking of animal life was a cultic act, which called for propitiation of the spirits. Elaborate food codes continue to characterize many of the world’s religions and cultures today. Vegetarianism and its variants may be prompted by a variety of ideological considerations, but contributing to these lifestyle choices may also be a desire to recover this sense of the sacredness of nature.
Dietary dilemmas also result from the cultural bias of positivism, according to which that which is unproven as to its efficacy is without value and should be eschewed. It ought to be obvious that such a position does not make a lot of sense. Science is a guide to life, but a partial one as much remains unknown and much, perhaps, unknowable in scientific terms. Even the mechanism of action of many widely accepted medicines is still unknown to science, their efficacy having been shown only through epidemiological studies with the initial therapeutic hypothesis sometimes due to no more than chance. If you’re confused by nutritional advice, you’re not the only one: we know a few things scientifically but there is a very great deal which we do not.
Furthermore, why does the dominant cultural paradigm – or ones personal conditioning through upbringing – get to be the unquestioned baseline relative to which all deviations need to be justified? As we do not get to put our lives on hold pending scientific advances, we need practical tools to make decisions, and culture is an unreliable guide. So what might these tools be? The following video presents one perspective on how to link science to decision making under complexity and uncertainty: the first ten minutes will give you the flavor and the first example. There is also a text version of the presentation.
Though worthwhile as a tool, I am not sure how applicable I find this approach to be in the general case. De facto, a number of people would doubtless cite not only science and values as a guide to decision making, but also hunches/their inner voice, self-observation and the precautionary principle. This “inner voice” represents a type of knowledge the nature of which bears further consideration. It seems (at least to me subjectively) that our body has some sense of the nutrients which it requires at any given moment – an innate nutritional intelligence – and that when we make decisions related to procuring nutrition, for example when shopping, preparing food or choosing from a menu at a restaurant, this innate intelligence plays a role, together, of course, with many other factors which may be less nutritionally relevant (emotional associations with particular foodstuffs, physiological addictions, what we have been told about food, what our choices communicate …). The reality of such a sense is well illustrated by the phenomenon of cravings during pregnancy – these appear to be informative of physical needs (although this has not been proven) even if there is unarguably merit to interposing a reflective act between the drive and its gratification, as the linked article suggests. At the same time, it is hard to believe that if he were left to make all the decisions himself, my son would naturally gravitate towards a healthy diet (unless, perhaps, I were to release him into the wild). We also have an innate ability to learn from our experience of certain foods which, perhaps largely subconsciously, feeds back into future decision making.
Explaining how this innate nutritional intelligence works, distinguishing it from other neurophysiological mechanisms, and determining the confidence we can have in it in making nutritional decisions is a serious philosophical and neurobiological problem which we are not even close to understanding (and some philosophers such as Thomas Nagel and Colin McGinn even argue that the mind-body problem, of which this is an instance, is intrinsically insoluble).
Not only cravings, of course, are informative as to nutritional needs; the way our body responds to food also contains a wealth of information if we are able to tune into it. Mostly, though, we are unaware of how specific foods affect our moods, energy levels and sleep patterns – and in the long run our health. We may have a hack. In the coming years, biofeedback is set to transform our ability to monitor and quantify our bodies’ reactions to food and guide us in nutritional, as well as wider lifestyle, choices, as the following video explains.
Finally, the Paleo way of reasoning does have some attraction, especially as a heuristic in the absence of more conclusive science. A particularly obvious example is Vitamin D, barely available from dietary sources and requiring sunlight for synthesis by the skin. A population which is mostly deprived of sunlight and, when it is exposed to it, rarely allows it to reach more than a few square centimeters of skin, is likely to be Vitamin D deprived, and no adaptation can produce something from nothing. To me it seems likely that we all suffer from chronic Vitamin D deficiency, and clinical guidelines as to healthy levels probably understate requirements to a significant degree. I supplement five times the recommended daily intake, and this is less than some sources recommend. Another iconic debate concerns the ratio between omega-3 and omega-6 fatty acids, which paleonutrionists argue would have been 1:1 in ancestral populations, citing a range of health issues connected with omega-6 preponderance. As flax is the only terrestrial plant which naturally has more omega-3 than omega-6, a balance of the two implies an ancestral diet rich in fish, seafood and seaweed. I am not sure I fully buy the 1:1 argument, but the considerable imbalances in fatty acid ratios in meat and eggs caused by feeding cattle and poultry an unnatural diet do cause me concern. Of course it’s not only a question of diet, but of lifestyle overall. Mark Sisson explains.
A last point I want to raise is the esthetics of food and its role in social bonding. A very recent study on chimpanzees came to the very surprising conclusion (for anyone familiar with chimp behavior) that sharing food increases the level of the pleasure neurotransmitter serotonin both on the part of the giver and of the receiver: just as it surely does for humans. Here is a summary. And average serotonin levels over the long term very definitely correlate with health. Peer pressure and cultural biases may result in bad nutrition, but there is still a trade-off between sticking to whatever dietary principles one has and engaging in rewarding social exchanges around food – like hopefully this discussion. Clearly, the esthetic pleasure derived from food is also a source of dopamine, at least typically: though the pathway can be reprogrammed when we neurotically obsess about the consequences. Dopamine similarly regulates cardiovascular health (and don’t let’s forget oxytocin: experts recommend a minimum of eight hugs a day). Emotional eating often seems like a problem, but perhaps it is merely a symptom inviting us to deeper self-enquiry:
What about you? What ethical precepts or other guidelines do you use when thinking about your food choices? Do you have ideas of your own to share with the group? Let’s get the discussion going!