Having become the fire Vaisvanara, I abide in the body of living beings and, associated with the Prana and the Apana, digest the fourfold food.
In simple words
Krishna describes his presence inside every body: "I become the digestive fire inside every living being. Working together with the incoming and outgoing breath, I digest the four kinds of food that people eat."
Word-by-word meanings
अहम्Iवैश्वानरः(the fire) Vaisvanaraभूत्वाhaving becomeप्राणिनाम्of living beingsदेहम्the bodyआश्रितःabidingप्राणापानसमायुक्तःassociated with Prana and Apanaपचामि(I) digestअन्नम्foodचतुर्विधम्fourfold
15.14 अहम् I? वैश्वानरः (the fire) Vaisvanara? भूत्वा having become? प्राणिनाम् of living beings? देहम् the body? आश्रितः abiding? प्राणापानसमायुक्तः associated with Prana and Apana? पचामि (I) digest? अन्नम् food? चतुर्विधम् fourfold.Commentary The immanence of the Lord as the gastric fire in all living beings is described in this verse.Vaisvanara The fire that abides in the stomach. This fire is fanned by the bellows of the incoming and the outgoing breaths continuously and large antities of food are digested. Inside the wonderful laboratory of the stomach I digest the food by taking the form of this gastric fire.Four kinds of food (1) Food which has to be eaten by mastication (Bhakshyam). (2) That which has to be sucked in (Bhojyam). (3) That which has to be licked (Lehyam). (4) That which has to be devoured or swallowed (Choshyam). Another classification is as follows (1) Rice is PrithiviAnnam (solid food) for human beings. (2) Water is Apyannam (watery food) for birds like the Chataka. (3) Fire is Tejasannam (hot food) for certain creatures. (4) Air is Vayvannam (air as food) for serpents.अयमग्निर्वैश्वानरो योऽयमन्तः पुरुषः येनेदमन्नं पच्यते।।This fire which is within man and by which the food is digested is Vaisvanara. (Brihadaranyaka Upanishad 5.9.1)He who thinks or meditates and feels that the Vaisvanara fire is the eater? that the food eaten by the fire is the Soma (moon) and that the two together form AgniSoma is not contaminated by the impurities in the food. He who meditates before he takes his food that the whole world which is in the form of eater and eaten is made up of Agni and Soma? is not tainted by the evil arising from eating bad food.Repeat this verse daily before you take your food. You will be free from all taints of impurity in food.
Contemporary scholarly and practical interpretations for modern seekers.
This interpretation draws on a specific tradition and may not represent the view of any single school. For authoritative guidance within a specific tradition, seek a qualified teacher.
Modern
I dwell in the hearts of all living beings as Vaishvanara, the cosmic fire of consciousness. Through me, the vital heat of life flows through every body, and without this warmth, the physical form becomes inert. The digestive fire that transforms food into the vital essence of life, generating the body's heat and enabling the internal organs to function naturally—all of this occurs without conscious effort or awareness on the part of the individual. The gastric fire within all creatures, which digests food, is itself an expression of the Supreme Self, known here as Vaishvanara.
I digest all four types of food. A healthy being's digestive power can assimilate all varieties of nourishment. The fourfold classification of food is based on the manner of consumption: first, that which must be chewed with the teeth, such as bread; second, that which is swallowed, such as milk; third, that which must be sucked, such as mangoes and sugarcane; and fourth, that which must be licked, such as honey and condiments. Within these four categories are encompassed all forms of sustenance—with flesh and without, cooked and uncooked. The transformation and digestion of all food consumed through the mouth is made possible only through the digestive process, and this capacity itself is an expression of the Supreme.
Animated by the vital forces of inhalation and exhalation, all creatures receive and expel through these processes. Yet a deeper meaning may be understood here: the conscious Self not only digests the food received as Vaishvanara, but also manifests as the vital breath, drawing the consumed food down through the esophagus to the stomach. After digestion, this same Self empowers the intestines to expel waste. In essence, the Supreme assists us in the consumption of food, its digestion, and the elimination of what is unnecessary.