Hi Nisha,
Others might want to add to what I can say about being "too yang". A property of yangness is constriction. One illustration is a child throwing a red-in-the-face temper tantrum. The blood vessels constrict and the face gets red. The child is probably sqeezing their eyes tight shut and mouth also, and probably holding their fists in front in a tight squeeze, maybe stamping feet also. Contained within the temper tantrum is anger, ego-centric selfishness, willfulness, --there is a power being exerted over others to get one's way. Adults do the same thing in a more hidden, socially acceptable manner. Rigidity of thinking, narrow focus, sometimes hatred, anger, resentment, and hostility towards others, and stubborness are yang traits. Impatience and short-temper is a good indication that one is becoming "too yang". Most people know what the tension of eating food overladen with salt does to them -- it makes one uptight, impatient, and ready to blow off steam at the first person who glances sideways. PMS is a good example of a "too yang" state. A woman is supersensitive to salt and bloating during PMS, with the resultant moodiness and emotional tension. On the other hand, extreme yang in men is seen as violence in its many varieties.
Probably the most horrific characteristic for macrobiotic people of those gone "too yang for too long", is their complete inability to see themselves objectively. There is a perception that, "I am always right, and I know what I'm doing." Others can see objectively what condition that person is in, but they themselves, just cannot see it.
If one has an overly yin condition, dis-ease, illness and needs to balance it for good health, --it is good to maintain a narrow "healing practice" of the macrobiotic diet and lifestyle in the beginning. As the condition improves, it is important to widen our practice and go-with-the-flow of one's bettering condition. If this isn't done, --then there is a danger of becoming "too yang", unnecessarily, and therefore, becoming unable to accurately see one's present condition. This can lead to sometimes life-threatening complications as deadly as the yin condition a person first started with!
Nancy