I don't buy it. It bears repeating: nothing you eat changes your body's pH. Nothing. Your urine's pH might chance a little, but nothing else.
If you want to try how does it feel when your blood pH changes, take a deep breath and hold it for a few minutes. The increased amount of carbon dioxide in your blood will make it more acidic than anything else will.
And someone please explain what are these "acid-forming compounds"? Amino acids? (lol)
Also, all these nutrients, acidic or not, will get to the kidneys via blood vessels. I fail to see how these acid components can have any noticeable "load" on the kidneys without showing any kind of pH change in the blood itself. And remember that if the pH of your blood changes, you die.
I'm having a hard time seeing how this would work. Aside from the fact that fruits and veggies are, gasp, good for you. You should eat more of them.