What is Wholesome and What is Unwholesome food?

एवंवादिनम् भगवन्तमात्रेयम् अग्निवेश उवाच ---- 

कथमिह भगवन् ! हिताहितानाम् आहारजातानाम् लक्षणम् अनपवादम् जानीमहे ; 

हितसमाख्यातानाम् अहितसमाख्यातानाम् च 

मात्रा-काल-क्रिया-भूमि-देह-दोष-पुरुष-अवस्था-अन्तरेषु विपरीतकारित्वम् उपलभामहे इति॥३२॥

तमुवाच भगवानात्रेयः -- यद् आहारजातम् अग्निवेश समान् चैव शरीरधातून् प्रकृतौ स्थापयति 

विषमान च  समीकरोति एतद् हितम् विद्धि ; विपरीतम् तु अहितम् इति

इत्येतद् हिताहितलक्षणम् अनपवादम् भवति॥३३॥

Translation : When Aatreya said this Agnivesha asked him " Oh Lord ! How we are to know the definition of wholesome and unwholesome foods without exception? And how are we to know the reversal of wholesomeness and unwholesomeness of described foods with changes in amount, time, preparation,region state of body, state of Dosha, individuals,and stages (of diseases) ?

Aatreya said to him " Agnivesha ! Whatever food that will enhance only the dhatus which are in equilibrium and restores equilibrium of the unbalanced dhatus is wholesome and the opposite is  unwholesome. This is definition of wholesome and unwholesome without exception.

Commentary (chakrapani) :  Agnivesha is pointing to difficulty in knowing the wholesomeness and unwholesomeness due to the factors which modify the nature of food. Wholesome becomes unwholesome and unwholesome may become wholesome due to factors like amount etc.For example

Wholesome foods like Red rice if taken in excess or in very small quantities become unwholesome.

The light foods like red rice etc. will become unwholesome in Hemant ritu when Agni is very strong.

Of the two types of Time here universal time is to be assumed as the other time i.e. stages of disease etc. is stated separately as Avastha.

Kriya is processing. Improperly washed or boiled red rice becomes unwholesome. 

Red rice produced in Aanup desha ( Wet and humid regions) becomes unwholesome.

In an obese person red rice becomes unwholesome due to its lightness It is stated in chapter 21 that for obese people food should be heavy and reducing.

Red rice is unwholesome for Vata. Dosha also includes diseases here. 

In childhood there is predominance of Kapha and bitter foods are wholesome but the same become unwholesome in old age due to predominance of Vata. Change in status relates to all factors like amount etc.

Similarly unwholesome food becomes wholesome depending upon quantity etc.

Aatreya is stating the principle. He is not assigning wholesomeness or unwholesomeness to any specific food article but saying that food becomes wholesome or unwholesome due to factors like quantity etc.

Commentary (Vishnu) :   So far most of the verses in this chapter were एकीयसूत्र or opinions of others. Here we are considering शिष्यसूत्र  and गुरुसूत्र (Query by disciple and explanation by the Guru). This indicates that with Aatreyas resolution of the discussion the symposium is over and normal teaching learning process has resumed. Agnivesha is asking a very specific question and Aatreya is answering unequivocally.
In the query Agnivesha is demanding a definition which is without exception. 
While giving such definition 

(H2B) लक्षण

n. accurate description , definition , illustration  Monier Williams Sanskrit-English Dictionary

Aatreya is not specifying any food item. Wholesomness and unwholesomeness is to be decided by the effect of the food on Dhatus which include Dosha, Dhatu, Mala, Agni, Kriya(The meaning here is physiological processes) Sense organs and mind and even soul. Any food which will maintain the equilibrium of all these is termed wholesome and any food which disturbs equilibrium of these is termed unwholesome. Here we should consider two more verses stated elsewhere. 
किञ्चित् दोषप्रशमनम् किञ्चित् धातुप्रदूषणम् ॥

स्वस्थवृत्तौ मतम् किञ्चित् त्रिविधम द्रव्यमुच्यते॥

Matter is of three types: 
1. That which restores equilibrium of Doshas
2. That which pollutes or vitiates Dhatus
3. That which is wholesome for a healty person for long term use


First type is called as drug or medication as it is useful in conditions where equilibrium of Doshas is disturbed (Diseases)
Second type is called a poison as it has deleterious effects on health
Third type is called food as it can be used as staple for a long term (sometimes lifelong)


Same article can be used as any of the three types.
For example: Yogurt or curds 
It becomes a drug when used in Vishamajwara. Peenasa, Atisaara, Sheetajwara, Aruchi, Mootrakrichhra and Thinness  (Ref. Charaka Sootrasthan 27/226) 
It becomes a poison when used in Sharad, Greeshma and Vasant Ritus, Raktapitta and all Kapha diseases.
It is usually used as food and increases Agni, used for weight gain, Aphrodisiac etc.


Another example Vatsanabha or Aconite
Normally it is a poison
When used after Shodhana and Marana it is an excellent drug used in many ayurvedic formulations.
Ashtang Sangraha prescribes it as an additive to foods in a very small dose as a Rasayana


Bhallataka
It is poisonous every time to those who have allergy to it.
Used as drug in many conditions and best for dry piles.
Charaka describes its long term use as Rasayana,
Its nut collected in specific conditions (Called Godambi) is very nutritious dry fruit used alongside almonds and apricots.


In short any material can be used as food, drug or poison and classification depends upon the effects produced in the body. 


This approach to  food materials is very different from moder nutritional approach as the latter depends predominently on food articles or Dravya and not on its Karma or outcome.

Second important verse 
समदोषः समाग्निश्च समधातुमलक्रियः॥

प्रसन्नात्मेन्द्रियमनाः स्वस्थ इत्यभिधीयते॥ Sushrut Sootrasthana 15/44


One whose Doshas, Agni, Dhatus, Malas, Bodily functions are in equilibrium and whose sense organs, mind and Soul are clear , bright , pure and perspicuous is called as Swastha or healthy person. 
Therefore Wholesomness and unwholesomeness is to be decided by the effect of the food on Dhatus which include Dosha, Dhatu, Mala, Agni, Kriya(The meaning here is physiological processes) Sense organs and mind and even soul 

Crux of the chapter

अथात्रेयस्य भगवतो वचनमनुनिशम्य पुनरेव वामकः काशिपतिरुवाच भगवन्तमात्रेयम् -

भगवन् !  संपन्निमित्तजस्य पुरुषस्य विपन्निमित्तजानाम् च रोगाणां किममभिवृद्धिकारणमिति॥३०॥

तमुवाच भगवान् आत्रेयः हिताहारोपयोग एक एव पुरुषवृद्धिकरो भवति , 

अहिताहारोपयोगः पुनः व्याधिनिमित्तमिति॥३१॥

Translation : After deliberating upon Lord Aatreya's statement, once again King of Kashi, Vamaka said to Lord Atreya " O Lord ! What is the cause of growth of Purusha generated from wealth (Excellent condition) of factors and of diseases generated by defects in the same factors ?"

Lord Aatreya said to him " Only the use of wholesome food is the cause of growth of organisms and use of unwholesome food is cause of growth of diseases.

Commentary (Chakrapani) : The word Eka Eva is used here to show the predominance or supremacy of wholesome food and not to rule out other causes like behavior, sleep and sound etc. quoted elsewhere. In the word व्याधिनिमित्त the middle term  अभिवृद्धि is hidden as the question refers to cause of growth. Unwholesome food is already mentioned as cause of origin of diseases. Or unwholesome food is cause of origin and growth of diseases and therefore middle term is omitted.


Commentary (Vishnu) : The crux of the whole chapter is stated in this pair of verses. Whatever may be the origin of an organism or it's diseases; the progress of disease can be controlled through use of wholesome food. This is the take home message of this whole chapter. Healthy growth of organism is also dependent on use of wholesome food. Here the emphasis is not on just food items but the whole galaxy of factors like quantity, timing, surroundings, combinations state of previous diet etc. In short emphasis is on usage. Just as grammatically correct word usage leads to lucidity in meaning; correct usage of food from health point of view  leads to easy attainment of health, growth and longevity. 
Chakrapani has correctly pointed out the caveats and meaning between the lines. 
Just as proper use of food leads to health improper use is cause of both origin and growth of diseases. 
Sushrut says ' संक्षेपतः क्रियायोगो निदानपरिवर्जनम्॥ '  Avoidance of causative factors is treatment in brief. As long as causative factors are continuing the disease process will not stop or reverse. When causative factors are no longer operative the natural tendency of Doshas is towards restoration of equilibrium ( स्वभावोपरम सिद्धान्त ) is one of the basic principles of Ayurveda. This tendency is inbuilt in all organisms. This tendency is both necessary and sufficient in any organic system. In my opinion it is an Evolutionarily Stable Strategy (ESS) without which organisms cannot survive and reproduce. 
Therefore 
1. Stoppage of improper use of food and 
2.Proper usage of wholesome food 
are the two extremely important arms of correct treatment.  Both are necessary and in most of the diseases sufficient. Medicines play a minor role if these two arms are properly used. 

Resolution by Atreya Punarvasu

तथर्षीणाम् विवदताम् उवाच एवम् पुनर्वसुः॥

मा एवम् वोचत तत्वम् हि दुष्प्रापम् पक्षसंश्रयात्॥२६॥

वादान् सप्रतीवादान् हि वदन्तो निश्चितान् इव॥

पक्षान्तम् नैव गच्छन्ति तिलपीडकवत् गतौ॥२७॥

मुक्त्वैवं वादसंघट्टम् अध्यात्मम् अनुचिन्त्यताम्॥

न अविधूते तमःस्कन्धे ज्ञेये ज्ञानम  प्रवर्तते॥२८॥

येषामेव हि भावानाम् संपद् संजनयेत् नरम्॥

तेषामेव विपद् व्याधीन् विविधान् समुदीरयेत्॥२९॥

Translation: When the Rishis were debating like this, Punarvasu said " Do not debate like that. Principle is very difficult to arrive at when everybody is taking a partisan stand. You are proposing theories and refuting others as if it is a foregone  conclusion. those who are going round and round like bulls in oil mill  cannot arrive at any conclusion. Leave this heated debate and think about the principle (Adhyatma) Unless crowd of dark (Tamas) thoughts are removed we cannot know the knowable.

(I propose) All those factors which when in excellent condition generate an organism; cause various diseases when (they are) defective.

Commentary (Chakrapani):    Blinding love with own theory is called here as Tamas Skanda as it interferes in arriving at conclusion. Factors like Mahabhootas are inclusive of Doshas like Vata as they are also made up of Mahabhootas. Various theories are put here to remove the doubt from mind of disciples.

Commentary (Y.G.Joshi): The Rishis were described as having infinite knowledge and dispelled doubts therefore every statement by them contained at least some aspect of the truth and must be considered deeply. Punarvasu is not refuting any theory but is advising against jumping to conclusions and not considering realistic objections while having blind faith in one's own theory. 

Commentary (Vishnu): Both Charaka and Sushruta have not sided with any perticular theory. They accept all the theories whenever suitable. This way of thinking is usually not seen in western thinking. Usually it is adversarial or argumentative way which is embedded in western scientific thought. Jain Darshana has a beautiful way of dealing with multiple theories i.e. Naikantvada. Modern Physicists are trying to build a grand unified theory which will explain everything. Einstein spent at least fifty years exercising his phenomenal intellect persuing GUT. String theory is supposed to be Theory of Everything (TOE) Though building a meta theory to account for all sorts of special situations  seems a worthwhile goal, consensus of Ayurvedic thinkers points to futility of such efforts. Here I am reminded of Godel's Theorum of incompleteness.For more details see the excellent book 

Gödel, Escher, Bach: An Eternal Golden Braid (commonly GEB) is a book by Douglas Hofstadter, described by the author as "a metaphorical fugue on minds and machines in the spirit of Lewis Carroll".

On its surface, GEB examines logician Kurt Gödel, artist M. C. Escher and composer Johann Sebastian Bach, discussing common themes in their work and lives. At a deeper level, the book is a detailed and subtle exposition of concepts fundamental to mathematics, symmetry, and intelligence.

Through illustration and analysis, the book discusses how self-reference and formal rules allow systems to acquire meaning despite being made of "meaningless" elements. It also discusses what it means to communicate, how knowledge can be represented and stored, the methods and limitations of symbolic representation, and even the fundamental notion of "meaning" itself.

In response to confusion over the book's theme, Hofstadter has emphasized that GEB is not about mathematics, art, and music but rather about how cognition and thinking emerge from well-hidden neurological mechanisms. In the book, he presents an analogy about how the individual neurons of the brain coordinate to create a unified sense of a coherent mind by comparing it to the social organization displayed in a colony of ants 

(Mathematicians Please correct me if I am wrong) Arriving at a meta theory may well be theoretically impossible. (Remember Heisenberg's uncertainty principle?) Whole quantum theory became possible only after scientists accepted this principle. Life sciences at current stage may move in different directions if we abandon our insistence about knowing everything from first principles. 

Summing up the various theories part 3

Summing up (Let us wait a little bit before Punarvasu Atreya's resolution of the discussion)

Theory	Proponent	Main argument	Refutation	Similar Modern Theory
Soul	Moudgalya Parikshi	Dead bodies do not have diseases	Soul desiring sorrow is a contradiction	Free will
Mind	Sharaloma	Mind under influence of Rajas or Tamas or both is responsible for behaviours which lead to diseases.	Mind without body has no meaning or existence	Strong anthropic Principle
Water	Vayorvida	Bodies do not exist in a vacuum and they need water based medium for their continued existence.	Soul, Mind,and many diseases can be shown as exceptions to Water Theory	Primordial soup in which first organism originated  is presumed to be watery (Supported by vast body of evidence) See also Madan’s comment
Six Dhatus	Hiranyaksha	Panchamahabootas represent material world or molecular world and Chetanadhatu. This includes Soul(Atman) accompanied by Logical mind (Manas), Ego or consciousness (Ahankara) and  Emotional mind (Chitta)	Presence of genetically inherited diseases cannot be explained by Six dhatu theory	Molecular biology covers Pancha dhatus but does not cover Chetanadhau
Inheritance	Kaushika	Every organism is unique. This uniqueness is imparted through inheritance.	All diseases are not inherited. Origin of first organism cannot be explained by theory of inheritance.	Genetics
Karma	Bhadrakapya	Behaviour, may it be instinctive or by free will, is an essential factor in generation of diseases.	Doer always precedes the deed	Madan’s comment is apt Epigenetics, The Human Microbiome and other such new areas of study are filled with surprises - enough to negate many contemporary gene- / genome-centric views and conclusions about health and disease
Nature	Bharadwaja	Everything occurs as per natures laws. No separate doer is needed for events to occur	If we opt for Swabhava vada (Nature Theory) then we deny free will for organisms.	Darwinian theory of evolution
Creator	Kankayana	The creator, Prajapati, Son of Brahma, on his own infinite free will created sentient and non sentient universe and all the pleasures and sorrows.	Prajapati who always looks after the best interest of his creations will not produce sorrowful conditions like a villain.	Weak Anthropic principle
Time	Bhikshu Atreya	Everything happens in the way it happens because it happens at that particular time		In the space time continuum it can be visualized as sand clock or two cones joined at apex. Past is a cone narrowing down to present and future is a cone expanding to infinite possibilities