Some months ago I started pondering the paleo diet, or some of its purveyors and adherents, as possibly embodying a concept akin to The Self-Justification Diet™. Understanding that this tendency springs from the confirmation bias we all share, I first broached the subject by pointing a satirical finger at myelf. The cognitive bias is bad enough in individuals, but when combining it with the social element of the herd instinct bias we may see a feed-forward effect resulting in self-assortment feeding ingroup bias which feeds back to our own confirmation bias. Since the paleo diet delves into areas of human instinct, it is basically impossible to prevent the propagation of certain ideas in a memetic fashion. As hinted in the title, the question of fat is a point I'd like to subject to some scrutiny in these terms.
In the paleosphere, there's a sometimes explicit, otherwise tacit, understanding that the SAD flourishes because of evolved human proclivities for sugar, salt, and fat. Our modern system of hunting and gathering from well-lit aisles and laminated menus hijacks the prehistoric nutrition plan delivered by our instincts. This narrative certainly isn't limited to the pop-evolutionary biology that's bantered about the pop-paleo community; it's recited in a variety of contexts...
I haven't heard anyone challenge the instinctual human drive for fat, salt, and sugar. Until further notice, I'll assume it's a generally accepted principle among the paleo community participants who believe the paleolithic was an actual period of time, before Adam and Eve, during which the genus Homo evolved.
It's on this foundational assumption that the paleo logical framework is formed - the very framework that provides an ultimate explanation for why our instincts aren't to be trusted regarding food choices in our mismatched grocery store and restaurant culture. It is this logical framework that underpins the large constituent of paleo proponents who minimize fruit consumption in outright defiance of the fact that fruit consumption in our evolutionary past was high enough to allow our genes that coded for vitamin C synthesis to be deactivated.
When it comes to fat, a rejection of the shoddy research of Ancel Keys seems to be all that's needed to make the logical leap to also rejecting the "lean game meat" conception of paleo forwarded by the likes of Loren Cordain, PhD. and Arthur De Vany, PhD. On the basis of the paleo logical framework, it's incongruent to reject the unrestricted consumption of fruit and also advocate the unrestricted consumption of fat. For that matter, it's similarly incongruent to reject grain consumption based on the paleo logical framework whilst recommending the unrestricted consumption of fat. If you like fat (and you do), fine. Eat whatever you want. But... keep in mind that there is almost certainly a limit to the amount of healthy fat consumption, and our heuristic "eat more fat" instinct will push some across the line into rationalization in service of self-justification.
"But... but... the science, Andrew... what about the science?"
The [paleo] positivist has little-to-no use for logical frameworks. In the grasp of positivism, logic is little more than a cutesy anecdote that may be useful for the generation of hypotheses. In this world of orthodox empiricism, claims cannot be made absent positive verification by way of controlled experimentation and commensurate data.
Unpacking this concept of paleo positivism reveals something. At its most fundamental core, paleo (whether we're relating it to diet or mind) is nothing more than logical framework. Perhaps strangely, this is true regardless of the depth of insight archaeology or anthropology may impart upon us with respect to any given question. Even if we knew exactly what a common ancestral population consumed across their lifetimes, it would remain necessary to invoke a (Darwinian) logical framework to begin to make prescriptive assumptions about what we should eat in the modern world. In its requisite minimization of the importance of the logical framework of paleo, positivist paleo renders itself an oxymoron - by definition. Despite that slight problem, it is still possible to act as a paleo positivist. The underlying truth is that the paleo positivist may as well simply be called a positivist.
The sure way to escape the positivist program is to recognize the value of paleo logic prima facie, or... as the null hypothesis. If that stance isn't taken, 'paleo' is little more than a rather hollow moniker.
Some may erroneously take the preceding paragraphs as an affront to science. That certainly is not my intent. Rather, my ardent rejection of positivist paleo is based on the sober recognition that science is likely to fall far short of definitively answering many important questions in our lifetimes. It's in these areas of incomplete research that our instinctual drives to consume are insidiously (read: unconsciously) blurred and obscured most acutely. To my mind, building a bridge from rejecting Ancel Keys (and/or the lipid hypothesis) to rejecting Dr. Cordain and Dr. De Vany is an area fraught with risk of this bias. Just as the modern apple and banana have been shaped by the sweet-tooth of H. sapiens, the modern meat supply has been shaped by our inherent lipid love - grass-fed included. Rather than adjudicating based on sparse data that appears to maybe kinda point one direction, I'm comfortable starting with the assumption that paleo logic provides valuable insight. And I'm not going to hold my breath while the science community plays the endless games of grants and funding and ethics panels and various other political wrangling.
Now if you'll excuse me, I found a new source of butter in the local grocery store. For some reason, they hid it in the cheese section.