Waste analysis is a medical diagnostic technique that involves analyzing urine or feces. It is a legitimate medical practice, but there is much CAM that uses it in a pseudoscientific way (see copromancy).
Proponents of the alkaline diet claim it is possible to see what the body's pH is by testing one's urine, and there are many expensive do-it-yourself urine testing devices available for this purpose. The basic foundation of the diet is that the blood is slightly alkaline, and that people should eat alkaline foods, in order to maintain the body's pH (promoters of this diet assume that the entire body has the same pH, for some reason). It is not possible to change the blood's pH with food, because any alkaline food is immediately neutralized by stomach acid, and even if it were possible, any significant change in blood pH would result in serious illness or death.
Even if the premise of the alkaline diet — that food can and should be used to change the blood's pH — were true, the urine testers would still be useless, as urine pH is not an indicator of the blood's pH, which remains relatively stable; changes in urine pH are due to eliminated food "ash," which does not affect the rest of the body, blood inclusive.
- Your Urine is Not a Window to Your Body: pH Balancing – A Failed Hypothesis, Science-Based Pharmacy.
- Acid/Alkaline Theory of Disease Is Nonsense, Gabe Mirkin, M.D, Quackwatch.