I don't know what's so demonstrably false about it; there is credible evidence (cited in another comment) suggesting mineral/electrolyte loss from drinking demineralized water and GGP admits to purposefully consuming nutrients from other sources to compensate. That only helps to prove my point?

If you have to compensate from other sources than I don't understand how something is necessarily harmless, without the qualifier that it should only be used in the context of a proper diet (which many/most don't have, particularly the types that might be susceptible to quack wellness claims)

Besides, one anecdote does not a disproven theory make