It is considered to be the end product of entire metabolism, or let us say, the fruit of it. Ooja is the protoplasm, life force or pure energy. According to Ayurveda, the food particles ingested in the body are converted to rasa or food juice, best part of rasa gets converted to Rakta (blood), best part of blood gets converted to Mansa(Muscles), best of which gets converted to Meda(Fatty tissue), Meda converts to form Asthi(Bone tissue),Asthi converts to Majja( Marrow) and marrow finally converts to Shukra(Sperms/semen), which is the essence of the body metabolism. Best part of Shukra gets converted to Ooja , which is the connection between the mind and the body.
The process of making Ooja reminds one of Geeta in which Krishna says that one in a millions has spiritual inclination; one among millions of such spiritually inclined people becomes a devotee, one among thousands of such devotees, tries to reach the ultimate and one among thousands of such devotees who are trying, finally reaches the destination and merges with the source of life.
It appears that our body is a process of continous progression from particle to energy. It feeds on the particle and converts it to energy, the life force, which gives vitality to the collection of organs and sets the mind and body to motion.
Ooja cannot be seen as only energy. But both its presence as well as the absence can be felt. Ooja influences mind as well as body.It is the basis of vitality in the body.
Ooja forms the aura of the body. Body can influence Ooja by external factors like attack of disease causing factors, but major influence comes from the mind. Habit of negative thinking and depression reduces Ooja or life force.
The health status of a person can be measured by the quantity of Ooja but body’s speed of making Ooja is more significant since if the speed is low then initial good amount of Ooja will gradually decrease with time.
Therefore the quality of food that we eat is very important as that provides the base for good or bad metabolism. According to Ayurveda, ideal food should be hot. The sequence of qualities of food is very significant, hot comes before fresh or well cooked, as hot food will be softer, help in maintaining good temperature for digestion and stimulate digestive juice secretion. Properties of ideal food are discussed under the topic – Qualities of an Ideal Meal.
The point is the food also should have prana (life factor), which signifies the ease with which it can be digested and converted to energy, creating minimum amount of toxins in the process.
Food that is rotten or stale is considered to be without prana or life energy, such food should not be consumed