Acid/Alkaline balance and other food selection systems
by Tom Billings

The terms acid and alkaline, when used in reference to food, normally refer to the pH (acid or alkaline) of the ash that results when the food is burned. As your digestive system is a kind of fire, the inference is that alkaline ash => alkaline in digestion, and in its effect on your body, with similar comments applying to acid ash food. This results in a class- ification of foods into the categories: acid, neutral, alkaline.
Most raw-foods diets are predominantly alkaline forming foods, though many fermented foods (raw sauerkraut, seed cheese, raw pickles, etc.) are very acid forming. Sprouting and soaking reportedly reduce the acidity of seeds and nuts.
The idea behind using acid/alkaline as a guide is to balance (or manage) the pH of your system. Excess acidity is regarded as bad for you - can cause headaches and stiff muscles. It is reported that your system "borrows" calcium from your central nervous system* to compensate for excess acidity elsewhere. Excess alkalinity is also reportedly bad - reportedly it can cause anxiety, muscle spasms. (* the myelin sheath surrounding your nerves is rich in calcium.)
Gabriel Cousens discusses the topic of acid/alkaline balance in his book "Conscious Eating". He suggests collecting a 24-hour urine sample (all urine passed in 24 hour period) and testing it for pH, using pH paper. This is a way to monitor the pH of your body. The idea of testing has some intellectual appeal, but the logistical aspects of collection are not so appealing!
Acid/alkaline balance is one of a number of food selection systems that one can use. A partial list of potentially relevant systems is as follows:
* eating to obtain a list of nutrients (Western nutrition) * acid/alkaline balance * balancing yin-yang (Traditional Chinese Medicine) * balancing/controlling the Ayurvedic humors - vata (air), pitta (fire), kapha (water) * eating to get all 5-6 tastes (Ayurveda, Traditional Chinese Med.) * food combining (Natural Hygiene, other systems) * mono-eating: eating 1 food, or 1 type of food, at a meal * sequential mono-eating, guided by senses (instinctive eating)
It would be nice if the above systems were consistent with each other, but life is not that simple. What one can do is to choose/use a system for general guidance, as you experiment to see which foods agree with you. The most important thing is how you personally react to a particular food, not the general claims of a particular system. Over time, you will learn which foods are good for you and which don't agree with you.
I would also advise against being too strict or too dogmatic regarding adhering to any particular system(s). Too many rules can make your eating stressful rather than nourishing and nurturing!