You have a balanced Autonomic Nervous System. This will be reflected in your Metabolic Dietary Type and nutrient recommendations.
The autonomic nervous system controls most of the involuntary activities of your body. It regulates your metabolism and keeps you alive without conscious thought. It has two opposing branches; the parasympathetic and sympathetic. The parasympathetic branch ("rest and digest") causes pupil contraction, lowering of heart rate, lowering of blood sugar, increasing of digestive secretions, and relaxing of the bladder among other things. The sympathetic branch ("fight or flight") does the opposite. Some nutrients strengthen one branch over the other. When an imbalance exists, these nutrients can make the imbalance better or worse. Different people have different dietary requirements.
The best source of information about Metabolic Typing is The Metabolic Typing Diet by William L. Wolcott and Trish Fahey, published in 2000.