I think traditional wisdom is both underrated, and overrated. Its something we dont use alot of these days, and we could stand to rely more on it. Theres some powerful medicine in herbs, plants and foods. Its a useful and productive system of knowledge, the subjective, intuitive and experential.
And yet, the body is extremely complex. Most things have both pros and cons. Whats an example...opium used to be used for poisoning (a long time ago). In fact, its not good at clearing toxins, but it does make the situation feel better. Tobacco was used by the native americans, but its a carcinogen (and so is their native sassafras). Cinnomin lowers the blood sugar, but it does so by altering the metabolism in other ways (more cellular heating, receded glut4 receptors).
Somethings are too complex, or too subtle for "wisdom" to pick up on. Many things in fact. Thats where we need medicine and science.
On the other hand of course, our modern minds tend to obfiscate the common sense, and the subjective. That way we miss things that should be self-evident, because we are waiting for 20 peer reveiwed studies to prove it.
I would not personally champion a way of eating, merely because its based on traditional practices and wisdom. That certain counts toward some intelligent practice, but it does not ensure their are no negative side effects.
I mean it goes without saying that traditional cultures are not aiming for optimal health, they are merely avoiding the more obvious harms, by their observable correlation with certain practices. A good form of intelligence, but hardly a perfect form of knowledge.
It somewhat depends on timespan, wisdom. If something has been done a certain way, for thousands of years, its probably better than something done for hundreds. But if one or two people slowly develop an illness from the practice, there is no way to make the connection, without understanding the mechanisms.
And moreso if everyone in the village or tribe, is at that point doing a range of potentially responsible behaviours. Either way people would just shrug their shoulders and put it down to bad luck, or evil spirits.
Paleo, on the other hand, tries to rely on genetics (what we are adapted to, rather than what we have experimented with in our landscape).
But paleo is also guesswork based on logic, and some evidence, just like traditional wisdom practices are guesswork based on experience and observation.
Id probably put some stock in information from both sources - the logic and science of the paleolithic (with tradition based on how many people did it, and for how many years) and science. Knowledge is elusive after all. People who beleive they have it, have not thought about the nature of knowledge.
I think you bring up an interesting issue in this idea of tradition/wisdom. For health direction: Some rely on the common sense of pre-agriculture, or pre-industrialism. Some rely on science and intellect, as well as beleif. I think its well worth considering into these other two, experience and subjective practice (tradition), and balancing them all against each other. They all have their faults and weakness, and are stronger when used together.
I actually beleive that a higher form of intelligence exists in the combination of the subjective and the logical, a form of knowledge that no society has exhibited, combined, and to its full potential, to date. But even still, you cannot have perfect knowledge.
I think the biggest problem with this presented conception of knowledge (and the one people commonly beleive in), is that its like a lost object. One day, your supposed to just find it after a long time looking.
But its more like looking for the ideal rock (you keep finding a better one, and throwing the other away), or better - trying to map out an island with flashlight in the dark. The search for knowledge is eternal, unending.
Basically put, to sum, subjective experience is underrated these days in terms of knowledge. We miss a whole load of things because we rely too heavily on "evidence" which is often itself biased, and not enough on what we learn, and intuit and experience.
But then again, that is all "wisdom" and tradition is, a period of collected experience and intuition. Observation cannot alone make all possible connections, it cannot fix to seeming or unseeming correlated elements into a causation. If it was a 100% superior form of knowledge to logic and science, wisdom would have discovered that tobacco was a carcinogen back in pre-colonial america etc.
Clearly both approaches have their benefits and failings.