Here is the web-page that contains several PRAL links and the formula itself:

https://phbalance.wikispaces.com/page/code/PRAL+Values

What do you think about this method?

I followed the food combining gurus with their acid/akaline theories for about 20 years while I was doing the vegan thing and the only thing that happened was that my health slowly deteriorated.  I think it's mostly nonsense and mumbo jumbo.  Lots of books, articles, and theories by popular diet gurus, but no real evidence that there is anything to it.  It also seems to be one of those fads that runs in cycles.  The health gurus grab onto it and sell a lot of books, it dies away for a few years, and then returns with a new crop of gurus.  It is constantly being reinvented with new and more complex criteria for evaluating foods for their acid/alkaline effect.

I certainly believe that our diet is the most important factor in determining our overall health, however, basing diet on some guru's unsubstantiated theory doesn't pass the reasonableness test for me anymore.  As I've changed my diet over the years, I've begun to require that any claims made by the proponents of a theory be supported by the available medical tests of the day.  In my case, I've made radical changes, and blood tests, x-rays, and the ability to drop medications have proven the benefits of the changes I've made - each year my annual physical shows me in better and better health.  I'm also able to measure some progress at home using glucose meters and the like.  Also, there is the experience of many others that have gotten similar results to mine.

Before I would again launch into the acid/akaline foods debate, I would want some objective way to test whether it was adding value or not.  I also would not take as gospel that changing urine or saliva from acid to akaline or visa versa is good or bad.  Remember that the medical profession thinks that ketones in the urine are abnormal yet many of us have found this to be a desirable state. 

So I guess the bottom line is to ask the question:  How do you propose to prove or disprove the acid/akaline food theory using an objective testing methodology that the rest of us can try to duplicate?  You might also ask:  What peer reviewed studies (independent of the gurus) have been published that support this theory.

You might also want to study the diet of our paleo ancestors and try to see where their diet falls on the latest iteration of the acid/alkaline food curve.  We can be pretty certain that the foods we evolved on are probably best for our on-going health, and if we eat those then the question of acid/alkaline is rather a mute point. 

Lex