On topics like this that have any chance of being politicized, don't just read Wiki - but actually look at what those numbers link to, go to them, and decide if you find them compelling. Because there will be entire sections of Wiki that are based on extremely fringe views. In other cases what is said on Wiki misrepresents what it links to.

The idea that paleolithic humans, in any significant number, may have been 'frugivores' - living off fruit, is based on a fringe book for which I was able to dig up very little other than a somewhat scathing review here, [1] concluding: "If there is any science that is influenced by our cultural background, expectations, and desires it is anthropology, and we must take care to make sure that what we want to be true doesn't obscure our vision."

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As for just 'sciencing' food, it doesn't really work because health is more holistic than basic measurables. Your example hits on one aspect of this. The motivation for 'real water' is because we've relatively recently learned that the human gut biome has a dramatic influence on our health and psychology. It even has a potential link to autism. I'm not ready to start going for 'real water' to address that but there are related issues.

For instance glyphosate was believed to be safe because it having no apparent reaction on the human body, but it turns out that (amongst other issues) it completely wrecks the human gut biome with effects that are not well understood. Yet if you look at the nutritional content or other measurables of e.g. glyphosate desiccated wheat, there's not going to be any red flags outside high levels of glyphosate. It's even a viable explanation for the odd rise of seemingly inconsistent 'gluten sensitivity'.

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Anyhow, point of that all being that we know what worked in the past, worked and worked extremely well. The dramatic rise of various issues in the present ranging from declining IQs, increasing obesity, falling testosterone levels, sharp increases in many forms of mental illness - autism not least of all, and so on - suggests that we're doing something, or more likely - some things, that are quite harmful to ourselves, but that we probably believe to be safe.

[1] - https://www.wired.com/2009/06/book-review-man-the-hunted/