Fasting :

The word fasting is technically represented by langhana and colloquially by upavasa. The word fasting, though literally denotes complete abstinence from food, Ayurveda generally do not advocate complete abstinence from food, but with certain exceptions of rule as in case of post shodhana therapy.

At one instance chakrapani in his commentary states the following as
the meaning of upavasa – upavāsaḥ krodhādiparityāgaḥ satyādyupādānaṃ ca, vacanaṃ hi- “upāvṛttasya pāpebhyaḥ sahavāso guṇe hi yaḥ| upavāsaḥ sa vijñeyo na śarīrasya śoṣaṇam” iti; || 1. dīrghañjīvitīyo’dhyāyaḥ 6|| Which opines that disassociation of the krodha, lobha, moha, iccha, dvesha etc. And following truth is upavasa. By doing so, one negates his sinful activities. But for that to happen a well fed physique will not cooperate, instead a poorly fed physique would cooperate. A physique devoid of food gets a little bit tired and the outward thinking based on one’s negative emotional thoughts like krodha etc. gets diverted since the focus of attention runs towards the appetite, there by relieving one from both his physical & mental stress!

Only hence abstinence from food depending up on one’s physical strength was being followed from generations to generations through some religious rituals like Ekadashi (11th day of Lunar month consisting of 28 days). He further says by following upavasa for a single day one may not end up with cachexia.

That being a spiritual explanation, now coming to the perspective of Ayurveda the Upavasa aka Langhana gets defined as “yat kiñcillāghavakaraṃ dehe tallaṅghanaṃ smṛtam” – means “that which causes lightness of the physique is langhanam”.

The qualities of langhanam are – it is light for digestion; sharp in potency; dry, rough & hard in consistency; subtle in its form; and is kinetic (laghūṣṇatīkṣṇaviśadaṃ rūkṣaṃ sūkṣmaṃ kharaṃ saram||kaṭhinaṃ caiva yaddravyaṃ prāyastallaṅghanaṃ smṛtam|). Chakrapani explains over the pretext of above verse, that, “Virukshana type of treatment causes reduction of unctuousness, whereas langhana causes reduction in heaviness of the body. (virūkṣaṇasya hi mukhyaḥ snehābhāvaḥ sādhyaḥ, laṅghanasya tu gauravābhāva iti sphuṭa eva bhedaḥ pratibhāti ||)

Upavasa is one amongst the 4 types of modalities of Langhana followed in Ayurveda. The other 3 being pipAsA (thirst); marutAtapa (exposure to breeze); pAcana (digestive compounds). (catuṣprakārā saṃśuddhiḥ pipāsā mārutātapau| pācanānyupavāsaśca vyāyāmaśceti laṅghanam||18||)

Who can be recommended for the procedure of Langhanam? :

• The exponentially aggravated combination of kapha, pitta, rakta and mala in association with vata; one with high tolerance or extreme physical strength. In either of these two contexts langhana (light food) followed by shodhana is advised to be prescribed or followed.
• The pacana type of langhanam has its jurisdiction over persons with moderate strength; kapha & pittaja diseases; nausea; vomiting; diarrhea; cardiac patients; visUcika; alasaka; fever; constipation; heaviness of body & body parts & loss of appetite.
• In addition, for persons with poor physical strength and mild diseases and those not feeling thirsty upavasa (easily digesting foods) are advocated.(prabhūtaśleṣmapittāsramalāḥ saṃsṛṣṭamārutāḥ| bṛhaccharīrā balino laṅghanīyā viśuddhibhiḥ||19|| yeṣāṃ madhyabalā rogāḥ kaphapittasamutthitāḥ| vamyatīsārahṛdrogavisūcyalasakajvarāḥ||20|| vibandhagauravodgārahṛllāsārocakādayaḥ| pācanaistān bhiṣak prājñaḥ prāyeṇādāvupācaret||21||).
  
  Upavasa is advised furthermore, in rasa vitiated diseases (rasajānāṃ vikārāṇāṃ sarvaṃ laṅghanamauṣadham| ||28. vividhāśitapītīyo’dhyāyaḥ25||).
• The stomach ailments; fevers of recent origin; hiccough; breathing ailments like bronchitis.(śāntirāmāśayotthānāṃ vyādhīnāṃ laṅghanakriyā| jvarasyaikasya cāpyekā śāntirlaṅghanamucyate||31|| tathā laghvaśanādyāśca jvarasyaikasya śāntayaḥ| etāścaiva jvaraśvāsahikkādīnāṃ praśāntayaḥ ||8. apasmāranidānam32||)
  
• In visucika type of dysenteries – langhana is preceded by virecana to address the ama involved in the aetiopathology of the condition, which need to be addressed through proper digestive quality of the langhanam during the physiological digestive stage. Eventually they eliminate the adherence of the doshas over the intestinal mucous membrane; regulate the peristalsis and thereby address the heaviness of abdomen and the aversion of food. This reversal of the pathology is not possible without the ignition of agni (agni sandukshanam) induced by the process of langhanam. (visūcikāyāṃ tu laṅghanamevāgre viriktavaccānupūrvī| āmapradoṣeṣu tvannakāle jīrṇāhāraṃ punardoṣāvaliptāmāśayaṃ stimitagurukoṣṭhamanannābhilāṣiṇamabhisamīkṣya pāyayeddoṣaśeṣapācanārthamauṣadhamagnisandhukṣaṇārthaṃ ca || 2. trividhakukṣīyavimānam 13||)
• In hemorrhagic conditions either langhanam or tarpanam (nutritional modalities) are to be followed depending up on the pathogenesis. In the sense the hemorrhagic tendency in the upper route as in epistaxis, the pitta in congruence with ama and its further association with kapha points the nidana (etiological factor) to snighdha guna which gets negated through the dry, sharp, subtle qualities of the langhana therapy. And other than the above said routes of hemorrhagic tendency (i.e. downward route & concentric route as in case of melena, rectal bleeding, IBS, Ulcerative colitis and puerperal skin bleedings, petechia respectively) the jurisdiction of treatment falls under the principle of tarpana (nutritious) in the form of yavAgu (gruel) & saktu (coarsely ground meal). (laṅghanaṃ raktapittādau tarpaṇaṃ vā prayojayet || 4. raktapittacikitsitam 30|| commentary: – tatrordhvamārgaḥ, sāmaṃ pittaṃ, kapho doṣaḥ, snigdhoṣṇaṃ ca nidānaṃ laṅghanaprayojakaṃ; tadvyatiriktaṃ tu mārgādi bhojanarūpatarpaṇaprayojakam| tarpayatīti tarpaṇamaśanam| tena yavāgūstarpaṇaṃ ca grāhyam| ye tu tarpaṇaśabdena saktutarpaṇameva grāhayanti teṣāṃ yavāgūdānapakṣo na saṅgṛhītaḥ syāt||29-30||).
• Acute inflammatory conditions as in carbuncle.{athāmajaṃ (shotha) laṅghanapācanakramairviśodhanairulbaṇadoṣamāditaḥ| 12. śvayathucikitsitam ||17||}
• In thyroid swellings, langhana along with kavala graham is advised. (galasya pārśve galagaṇḍa ekaḥ syādgaṇḍamālā bahubhistu gaṇḍaiḥ|…….syāllaṅghanaṃ vaktrabhaveṣu cāpi pragharṣaṇaṃ syāt kavalagrahaśca||12. śvayathucikitsitam 80||).
• Kaphaja diarrhea. (śleṣmātisāre prathamaṃ hitaṃ laṅghanapācanam|| 19. atisāracikitsitam 102||).Kaphaja skin ulcers. (bahupiccho guruḥ snigdhaḥ stimito mandavedanaḥ| pāṇḍuvarṇo’lpasaṅkledaścirakārī kaphavraṇaḥ||15||).
• Kaphaja pinasa (rhinorrhea) (gauravārocakeṣvādau laṅghanaṃ kaphapīnase| ||26. trimarmīyacikitsitam 149||).
• Tridosaja cardiac ailments. Though tridoshas are involved in the aetiopathology, hrdaya being the origin site of kapha langhana gets advised –(tridoṣaje ādau laṅghanavidhānaṃ hṛdayasya kaphasthānatayā tadgate tridoṣaje’pi kapha evādau laṅghanena jeya iti matvā kṛtam| tridoṣaje tūlbaṇadoṣacikitsāsūtramāha- hīnātītyādi| 26. trimarmīyacikitsitam /36).

Benefit of judicious dosage or usage of langhana chikitsa:

The judicious fasting provides the following benefits therapeutically,

• Accrues lightness of body
• Enhances unhindered elimination of flatus; urine and feces
• Symptom free regions of pericardium, throat
• Empty eructation
• Wards off the stupor & debility
• With the appearance of sweating, because of the langhana chikitsa the taste, hunger and thirst, which was defunct, previously gets functional.
• Amelioration of the Symptoms of the disease subjected to langhana – (vātamūtrapurīṣāṇāṃ visarge gātralāghave| hṛdayodgārakaṇṭhāsyaśuddhau tandrāklame gate||34|| svede jāte rucau caiva kṣutpipāsāsahodaye| kṛtaṃ laṅghanamādeśyaṃ nirvyathe cāntarātmani||35||).

Adverse effects of excessive indulgence in Langhana:

When indulged in excess the langhana certainly gets harmful and causes the following conditions.

• Suppression of hunger; thirst resulting in loss of appetite.
• Debilitated functioning of hearing and visual apparatuses.
• Confusion of mind (stupor) due to the vata moving upwards and getting stagnated in the precordial region.
• Exhaustion of physical strength; agni & bala (contextually refers to the mucosal lining).
• Pain in parvas (small joints like carpals; tarsals; metacarpals and metatarsals).
• Malaise.
• Manifestation of cough.
• Dryness in oral cavity.(kṣutpraṇāśo’rucistṛṣṇā daurbalyaṃ śrotranetrayoḥ||36|| manasaḥsambhramo’bhīkṣṇamūrdhvavātastamo hṛdi| dehāgnibalanāśaśca laṅghane’tikṛte bhavet||37|| parvabhedo’ṅgamardaśca kāsaḥ śoṣo mukhasya ca|).

Over a concluding note, the judicious application of fasting therapy with due consideration of indication, contra indications, when clinically adopted with appropriate method and dosage, is certain to provide the enlisted therapeutic benefits to the individual.