Bhagavad Gita: Chapter 15, Verse 14

अहं वैश्वानरो भूत्वा प्राणिनां देहमाश्रित: |
प्राणापानसमायुक्त: पचाम्यन्नं चतुर्विधम् || 14||

ahaṁ vaiśhvānaro bhūtvā prāṇināṁ deham āśhritaḥ
prāṇāpāna-samāyuktaḥ pachāmy annaṁ chatur-vidham

ahamI; vaiśhvānaraḥfire of digestion; bhūtvābecoming; prāṇināmof all living beings; dehamthe body; āśhritaḥsituated; prāṇa-apānaoutgoing and incoming breath; samāyuktaḥkeeping in balance; pachāmiI digest; annamfoods; chatuḥ-vidhamthe four kinds


BG 15.14: It is I who take the form of the fire of digestion in the stomachs of all living beings, and combine with the incoming and outgoing breaths, to digest and assimilate the four kinds of foods.


Scientists would attribute the forces of digestion to the gastric juices secreted by gall bladder, the pancreas, the liver, etc.  However, this verse reveals that such thinking is again simplistic.  Behind all these gastric juices is God’s energy that works to make the process of digestion possible.  The vaiśhvānara, meaning “fire of digestion,” is ignited by the power of God.  The Bṛihadāraṇyak Upaniṣhad also states:

ayam agnir vaiśhvānaro yo ’yam antaḥ puruṣhe

yenedam annaṁ pachyate   (5.9.1) 

“God is the fire inside the stomach that enables living beings to digest food.” 

The four kinds of food (chaturvidham) alluded to in this verse are: 1. Bhojya.  These include foods that are chewed with the teeth, such as bread, chapatti, etc.  2. Peya.  These are foods that are swallowed, such as milk, juice, etc.  3. Kośhya. These are foods that are sucked, such as sugarcane.  4. Lehya.  These include foods that are licked, such as honey, etc.

In verses 12 to 14, Shree Krishna explained that God makes possible all aspects of life.  He energizes the earth to make it inhabitable.  He energizes the moon to nourish all vegetation, and He becomes the gastric fire to digest the four kinds of food.  He now concludes this topic in the next verse by stating that He alone is the goal of all knowledge.