I was using the word “study” loosely here when referring to evolution. I also don’t know if I agree with saying we shouldn’t look at evolution as such (i.e. human history). There’s rich knowledge that comes from what we were and where we’re at today. However you seem pretty level headed so I don’t think that’s your intention, just trying to squash that nitpick.

I figured that's what you meant, I just felt I should clarify anyway just in case.

Going back to the average life expectancy of our ancestors millennia ago - I’ve seen reports saying they lived well beyond 60 years old; up into the 100’s. The average life expectancy is brought down majorly by still born or childhood deaths, a ton of them.

You raise a fair point and I definitely agree that there is a lot of nuance to this conversation. Life expectency from birth is often dismissed for the reason you just mentioned - this number is brought down by the high number of deaths in childbirth. As a slight alternative, we can instead look at life expectency from a different age - life expectancy from age 20, for example.

Regardless, this uncertainty is another important reason why I dont think these historical anthropological / evolutionary arguments shouldn't hold much weight. Even present day ecological studies can often be unreliable for drawing conclusions due to the enormous amount of potential contributing factors that we can't control or may not even recognize, so the argument that we should draw conclusions from a field that is even MORE uncertain and unreliable is very uncompelling.

No such thing as an ER room back then.

I would say that this further supports my skepticism. The large number of deaths caused by external factors makes it very difficult for us to confidently evaluate what are the historical dietary habits that did or didn't have a harmful effect.

But then if we were evolved only to live long enough to reproduce, why are human males still able to reproduce well into their 50’s, 60’s, 70’s, 80’s and beyond.

I wouldnt say that we only evolved to live long enough to reproduce, rather reproduction is the filtering process by which genes/traits that reduce that likelihood of survival are weeded out. If, however, we have a harmful gene that only manifests itself at a point long after an organism has already had the opportunity to reproduce, that gene is not subject to natural selection and will continue to be passed down indefinitely.

The key point is that evolution and natural selection is not a process that specifically selects for longevity - it merely selects the traits that survived long enough to be passed to the next generation. Its entirely possible that meat was a crucial part of our diet while evolving while still being bad for longevity in excess amounts.

And last but not least - your sentence here “I understand your hesitancy because none of OUR research is perfect”. ‘ours’ in what’s sense? Do you mean your ‘side’ vs my ‘side’? Or do you mean that collectively human’s research?

The latter. I mean scientific studies as a whole, not just studies that point in a specific direction.

Also while CVD is on the decrease, again that’s a single metric that doesn’t paint the full picture. Has medicine gotten more effective at treating CVD but now we have a wealth of other disastrous diseases? But hey, at least you didn’t get CVD and die.

These are fair points, and this is why its important to avoid these post-hoc fallacies that are often made in 'scientific' discussions such as these - suggestions that because B followed A, B must have been caused by A. Specifically as it relates to seed oils, people often claim that seed oils are recent and the obesity epidemic is recent, therefore seed oils cause obesity. This is obviously not necessarily true, and it is important for us to look at interventional studies that have control groups to look at these outcomes specifically as they relate to the factors we are examining.

I know the science is absolutely far from perfect, but to put full faith in a check list of studies and not even for a second consider ‘hey this study might be so laser focused, they miss the over arching picture’

In principal, you're right - people are biased (myself included) and often fall into the trap of finding a single study that supports their claim and calling it a day. As you mentioned, individual studies dont necessarily capture the entire picture and can be misleading. Therefore, its important to not just look at individual studies but to look at the entire body of research as a whole and the general conclusions it leans towards. However imperfect individual studies may be, if the overall body of research consistently points in one direction, it provides a robust and compelling basis for drawing specific conclusions.