According to Charaka Samhita, the Bible of Ayurvedic text, one should not take curd, a predigested fermented food, in the night. This rule of Ayurveda has created a lot of controversy between doctors of Ayurveda and modern system of medicine. In fact, both Chinese and Ayurveda medicine clearly documents that one should not combine fermented food with unfermented food after sunset.

The diurnal variation of digestive enzymes has shown that they are weak in the evening hours co-relating with Kapha period of Ayurveda (6-10 pm). As per Ayurveda during weak digestive fire period one should not take a combination of pre-digested and digested food.

Ayurveda classifies 6-10 AM period in the morning as slow Kapha period, 10-2 pm afternoon period as strong Pitta period and 2-6 am period as active Vata period. The 12 hours cycle then repeats with 6-10 evening Kapha, 10-2 am late night Pitta and 2-6 am early morning Vata period.

According to Ayurveda, food is first converted into sweet taste in the mouth, sour taste in the stomach, and then bitter taste in the large intestine depending on the stages of digestion.

Normally, combination of food does not harm as long as the time food stays in the stomach remains normal.

In presence of slow gastric movement, a condition called gastroparesis commonly seen in diabetics food may stay in the stomach for over two hours. In this situation due to mismatch of two categories of foods the pre-digested fermented food will go into a next stage of digestion leading to  gas formation, acidity, dyspepsia and gas. While the other non fermented food will tale its usual course of digestion.

Digestive fire being strong in Pitta period (10am to 2pm) this problem is not faced when curd is taken in lunch time. Similarly dosa, idli, dhokla are restricted for their use in the night.

Ayurveda also says that one should not take three substances in excess and they are Pippali (piper longum, long pepper), Alkali and Salt. Pippali intensify the action of drugs to which they are added and can cause interactions with many allopathic drugs. This point must be known to all allopathic doctors.  Pippali should not be used continuously for a long term.

According to Ayurveda, people who are accustomed to excessive use of salt suffer from premature baldness, early grey of hair, etc.

If one consumes excess salt intake it should be reduced gradually and not suddenly.

It is a well know fact that substances which should not be used in excess are not offered to God, as it is supposed to be bad for the spiritual health. .

Food should be taken in moderation in proper amount, with concentration and with awareness of all five senses, neither too slow nor in hurry.

About curd Ayurveda further talks that curd should only be taken along with ghee, sugar, green gram, honey or amlaka. It should also not be taken hot.

Oil, ghee, and honey are the alleviators of Vata, Pitta and Kapha, respectively and need to be used in the right quantity.

In modern science also it has been shown that a high-salt diet may increase the risk of developing gastric and duodenal ulcers. High concentrations of salt in the stomach induce gene activity in the ulcer-causing Helicobacter pylori bacterium that causes it to become more virulent.

Salt restriction also reduces the diastolic blood pressure by 2-8 mm Hg.

A recent WHO report, said that reducing salt intake would be a cost effective way to reduce the risk of developing high blood pressure directly and reducing the risk of heart attack and stroke indirectly. The report recommends people to reduce consumption of sodium to less than 2 gm per day for each person. Common salt is chemically called Sodium Chloride (NaCl2). About 2.5 gm of table salt contains one gm of Sodium. This would mean that about 5 gm of table salt is the current recommended level of consumption per day.

According to a report published from the All India Institute of Medical Sciences in the year 2000, the average intake of salt in India was 10 gm per day for each person. This would amount to about 4 gm of Sodium. The current recommendations suggest reducing this consumption by half.

A recent research study conducted by researchers at Harvard Medical School and published in the recent edition of the British Medical Journal, found that reducing salt intake by 25% reduced the risk of developing heart disease by 25% and reduced the chance of death from heart disease by 20%.

Adding a pinch of salt to milk will keep it fresh longer is a common internet tip for the population but traditional Ayurveda teaching goes against it.