According to Ayurveda Aharaparinamkara bhava is the ultimate fate of eaten food in living body. If eaten food is as per requisites of body entities, ‘ultimate fate of food’ facilitates health. Otherwise eaten food could be problematic to health.
Ingested food is bio-transformed into body entities. If food bears qualities facilitating body entities, it is able to nourish and replenish these body entities. If food bears qualities opposite to body entities, such food is capable of killing these body entities. Hence ‘ultimate fate of food’ is to either facilitate or opposes body entities. Factors which make food to undergo ‘ultimate fate’ are called ‘Aharaparinamkara bhava’.
In other words we can say that taking food only do not nourish the body, but rather it should be digested properly or biotransformation of food should be appropriate within the body. There are many factors which affect the process of digestion which is called Aharaparinamkara bhava. The factors responsible for bio-transformation of food are:
Ushma is parallel to Agni in word. Just as fire boils rice from raw grains, this ushma digests ingested boiled rice to absorbable products. This is the action of Agni or pacakaagni, as far as digestive system is concerned.
Similar thought is read in modern physiology of digestion. Maintenance of temperature (ushma) in digestive tract is extremely important for digestion. Digestive enzymes need typical temperature and appropriate pH in GI tract, without which digestion becomes impossible. Hence, this factor is directly responsible for digestion.
Vaayu or movements and stimulation of various kinds is supplementary in digestion
Other factors like vaayu are helpful in biochemical reactions of digestion of food. Vaayu drags food to proper place where Agni actually exists. Not only this but Samaana Vaayu also adds to stimulate Agni. This Agni is another help to digestion of food.
Supplementary functions of vaayu are-to induce secretion of enzymes in GI tract.
Similar thought is read in modern physiology of digestion. Movements of stomach, small intestine are in accordance to presence or absence of food; in presence of food, they are in accordance to facilitate and smoothen sown digestive functions.
Kleda is again necessary supplementary factor as it helps in disintegrating coarse food material into finer particles. Kleda is moisture. In digestion this moisture is provided by ‘Kledaka kapha’ in stomach or aamaasaya. Kledaka kapha soaks all food material whether taken with fluid or dry and makes a fine paste of chewed food in stomach.
Similar thought is read in modern physiology of digestion. Food coming from stomach is already in fine state. This is due to churningt movements of stomach as well as mucus in stomach. Duodenum sphincture does not allow coarse food to enter.
Sneha is in context to softness brought to food.
Similarly mucus in GI tract functions in the same fashion as read in modern physiology.
Kaala is considered in this context as time required for digestion. However efficient enzymes are, however effective movements are, food must get certain period to get digested
Similar thought is read in modern physiology of digestion. Retention of food for the purpose of admixture with enzymes and allied appropriate movements of GI tract are described in modern physiology.
Samyoga is healthy combination of food items. If food items are mixed in wrong way or in wrong proportion or are cooked in wrong blending; food becomes unhealthy for human GI tract.Similarly, for proper digestion other factors should also be taken into consideration such as; when to eat (time to eat), how much to eat (quantity of food), how to eat (process of eating), etc