纳（na） means appetite, which contains how much you eat and how well you can get from what you eat. In other words, it is how much you can absorb from the food. 差（cha） means bad， which is the opposite condition of good. So in a few words, the whole phrase 纳差(nacha) means you eat less and absorb little.
Na Cha belongs to stomach and spleens disease in Chinese medicine. It results from many fators, such as eating too much which can not be digested soon. Its symptom is vomitting some sour liquid, belch the gas which is sour too. Some other fator: if where is too much water in your body which can not easily expel, you will feel gastrectasia and your coat of the tongue will become more than before and it will become white and oily. Still, dyspepsia can lead to Na Cha, which is called “weakness of the spleen and stomach”. Its symptom is not only Na Cha but also gastrectasia after eating, having a yellow color on the face and turning thinner, short breath, and losing the interest to talk, diarrhea and so on.
Suggestions: take 7 or 8 lacerate Chinese Dates without pit, and ten or more medlars in a thermos. Pour some hot water to dip them for half an hour, then drink all of them. Pay attention, you should drink it after meal half an hour at least.
