That so bizarre - our bodies literally regulate ourselves to within 0.1 pH, and have 3 different mechanisms of maintaining it - why would we need or want to have a diet to adjust that? I know, you're just the messenger, and don't believe in it.

It started with the (vaguely somewhat plausible) notion of the acid ash hypothesis. Foods when fully oxidized can have a more acidic or basic ash, depending on the constituent elements. Phosphor and sulfur oxidize to the phosphate and sulfate anions, which are acidic, while calcium, magnesium, sodium, and potassium cations form hydroxides/carbonates. The theory goes that to maintain buffered pH, the body has to cations from somewhere, leaching it from bones.

Nowadays we know that most pH regulation is done with carbonate/bicarbonate via respiration, with ion transport managing electrolytes.

The alkaline diet has devolved to just throwing "bad" foods in the acidic bucket and "good" foods in basic, irrespective of chemistry:

https://waterforlifeusa.com/wp-content/uploads/2017/08/alkal...

That's bizarre. Do they dose themselves with CO2 to manage their body's alkaline pH then?