It often amazes me what bizarre claims people will believe, when just a moment's consideration would show how absurd, or at least suspect, they are. For instance, many of those critical of Western society, most notably those pushing some sort of "primitive diet", claim that this or that native society was notably more healthy until they encountered Western society and adopted our diet, especially "processed" foods such as sugar and flour. Two of the claims in particular come to mind, those being that such societies were free of diabetes, and never suffered from obesity, implying those ailments are the result of our "unnatural" way of eating.
Now, the diabetic claim is the more absurd, as it falls apart the moment one asks the most obvious question. After all, until Western society encountered these natives, exactly who would have diagnosed diabetes? The same problem exists with related claims, such as primitive people never suffered from cancer before encountering the West. Precisely who is keeping records of the incidence of cancer or diabetes prior to Westerners arriving? Some may claim they can question natives about causes of death, or something similar, but even there it falls apart, as it is pretty difficult to tell if a particular death was due to contagious illness, cancer or the complications of diabetes without Western techniques, or whether blindness was due to diabetes or parasites, limb loss due to diabetes, leprosy or some other ailment. Thus, in a word, there is no good data before Westerners arrive, and thus, no way to tell what ailments were or were not prevalent prior to encounter with the West. And, as encounter with the West commonly leads to rapid acceptance of Western products, these claims are fairly absurd*.
The claim of a lack of obesity is more plausible, but not exactly meaningful. As I discussed elsewhere ("The Hunter-Gatherer Mistake"), hunter-gatherer groups tend to have populations which hover at, or slightly above, the carrying capacity of their environment, with war or famine keeping the numbers at that level. Given a lifestyle where famine typically culls a large part of the population, one would not expect obesity to be common. However, that says nothing about the healthiness of such an existence. It merely says that the West excels at producing abundance.
There are other claims, many even more absurd, some about primitive societies in the modern world, others about prehistoric man**, but I think these two show the pattern pretty well. Nor are such claims limited to this topic. From environmentalism to economics to politics, such ludicrous claims are found everywhere in modern society, often underlying many popular beliefs. So I would ask, next time you encounter a bizarre claim backed by some facile reference to history, or primitive cultures, or some peculiar practice of a foreign land, ask yourself if it makes sense, if a moment's thought might undermine a seemingly perfect proof.
* Some fall back on earlier notes of anthropologists or medical aid workers, but those are not the same as real epidemiological data. Both tend to work in limited areas with relatively small groups, and thus hardly represent a good long term sample. Also, they tend to work for fairly limited spans of time. And, in the case of medical aid, they usually arrive at the same time as other Western aid, such as food, and so the population is already "contaminated" with Western ways.
** I recall an AM radio infomercial for colloidal silver which argued higher primitive oxygen values made primitive man much healthier. This ignores two rather significant facts. First, that too much oxygen, by favoring oxidation, is quite harmful. Second, that we don't have a bit of evidence showing primitive man was healthier than modern man. Then again, considering that they ignored the toxicity risk of silver, I suppose I should not be surprised.