Well that only can be done in many ways since the amount of sodium/potassium/calcium etc can vary with each tablespoon/teaspoon, etc, but you can use the following methods:
a. learn to decipher the body responses and adjust the amounts
b. use kinesiology like Invicible did above
c. use a dowsing method that can tell you the number of tablespoons of an ingredient to another amount of tablespoons/teaspoons of another ingredient (similar to kinesiology).
I guess there are also alternate methods, more posibilites to gauge, it's up to you to pick which method works best for you.