By development of Kṛṣṇa consciousness one can know that everything has its use in the service of the Lord. Those who are without knowledge of Kṛṣṇa consciousness artificially try to avoid material objects, and as a result, although they desire liberation from material bondage, they do not attain to the perfect stage of renunciation. Their so-called renunciation is called phalgu, or less important. On the other hand, a person in Kṛṣṇa consciousness knows how to use everything in the service of the Lord; therefore he does not become a victim of material consciousness. For example, for an impersonalist, the Lord, or the Absolute, being impersonal, cannoteat. Whereas an impersonalist tries to avoid good eatables, a devotee knows that Kṛṣṇa is the supreme enjoyer and that He eats all that is offered to Him in devotion. So, after offering good eatables to the Lord, the devotee takes the remnants, called prasādam. Thus everything becomes spiritualized, and there is no danger of a downfall. The devotee takes prasādam in Kṛṣṇa consciousness, whereas the nondevotee rejects it as material. The impersonalist, therefore, cannot enjoy life, due to his artificial renunciation; and for this reason, a slight agitation of the mind pulls him down again into the pool of material existence. It is said that such a soul, even though rising up to the point of liberation, falls down again due to his not having support in devotional service.
(Bhagavad-Gita----2:63----purport).

The devotees of the Lord are released from all kinds of sins because they eat food which is offered first for sacrifice. Others, who prepare food for personal sense enjoyment, verily eat only sin.
The devotees of the Supreme Lord, or the persons who are in Kṛṣṇa consciousness, are called santas, and they are always in love with the Lord as it is described in the Brahma-saṁhitā (5.38): premāñjana-cchurita-bhakti-vilocanena santaḥ sadaiva hṛdayeṣu vilokayanti. The santas, being always in a compact of love with the Supreme Personality of Godhead, Govinda (the giver of all pleasures), or Mukunda (the giver of liberation), or Kṛṣṇa (the all-attractive person), cannot accept anything without first offering it to the Supreme Person. Therefore, suchdevotees always perform yajñas in different modes of devotional service, such as śravaṇam, kīrtanam, smaraṇam, arcanam (S.B.7:5:23), etc., and these performances of yajñas keep them always aloof from all kinds of contamination of sinful association in the material world. Others, who prepare food for self or sense gratification, are not only thieves but also the eaters of all kinds of sins. How can a person be happy if he is both a thief and sinful?
(Bhagavad-Gita----3:13--- translation and -purport).

When Lord Kṛṣṇa is worshiped, the demigods, who are different limbs of the Lord, are also automatically worshiped; therefore there is no separate need to worship the demigods. For this reason, the devotees of the Lord, who are in Kṛṣṇa consciousness, offer food to Kṛṣṇa and then eat—a process which nourishes the body spiritually. By such action not only are past sinful reactions in the body vanquished, but the body becomes immunized to all contamination of material nature. When there is an epidemic disease, an antiseptic vaccine protects a person from the attack of such an epidemic. Similarly, food offered to Lord Viṣṇu and then taken by us makes us sufficiently resistant to material affection, and one who is accustomed to this practice is called a devotee of the Lord. Therefore, a person in Kṛṣṇa consciousness, who eats only food offered to Kṛṣṇa, can counteract all reactions of past material infections, which are impediments to the progress of self-realization. On the other hand, one who does not do so continues to increase the volume of sinful action, and this prepares the next body to resemble hogs and dogs, to suffer the resultant reactions of all sins.
(Bhagavad-Gita----3:14----purport).

The human being is meant for self-realization, and for that purpose he is not to eat anything which is not first offered to the Lord. The Lord accepts from Hisdevotee all kinds of food preparations made of vegetables, fruits, leaves and grains. Fruits, leaves and milk in different varieties can be offered to the Lord, and after the Lord accepts the foodstuff, the devotee can partake of the prasāda, by which all suffering in the struggle for existence will be gradually mitigated. This is confirmed in the Bhagavad-gītā (9.26). Even those who are accustomed to eat animals can offer foodstuff, not to the Lord directly, but to an agent of the Lord, under certain conditions of religious rites. Injunctions of the scriptures are meant not to encourage the eaters of animals, but to restrict them by regulated principles.
(Srimad Bhagavatam----1:13:47----purport).

A human being is not to eat anything which is not offered to the Supreme Personality of Godhead. Yajña-śiṣṭāśinaḥ santaḥ: one becomes freed from all sinful reactions by eating foodstuffs which are offered to Yajña, the Supreme Personality of Godhead. A devotee therefore eats only prasāda, or foodstuffs offered to the Supreme Lord, and Kṛṣṇa says that when a devotee offers Him foodstuffs from the vegetable kingdom, with devotion, He eats that. A devotee is to offer to Kṛṣṇa foodstuffs prepared from vegetables. If the Supreme Lord wanted foodstuffs prepared from animal food, the devotee could offer this, but He does not order to do that.
(Srimad Bhagavatam----3:29:15----purport).

The devotees of Lord Viṣṇu are also His expansions. They are called vibhinnāṁśa. Lord Viṣṇu is offered all kinds of sacrificial ingredients, and because devoteesalways eat prasāda, the remnants of His food, the scent of sacrificial ingredients emanates not only from Viṣṇu but also from the devotees who eat the remnants of His food or the food of His devotees. Āgnīdhra considered Pūrvacitti an expansion of Lord Viṣṇu because of the pleasing scent of her body. Aside from that, because of her jeweled earrings, shaped like sharks, because of her scattered hair, resembling bumblebees mad after the scent of her body, and because of the white rows of her teeth, which resembled swans, Āgnīdhra compared Pūrvacitti's face to a beautiful lake decorated with lotus flowers, fish, swans and bumblebees.
(Srimad Bhagavatam----5:2:13----purport).

As stated in Bhagavad-gītā (3.13):
yajña-śiṣṭāśinaḥ santo
mucyante sarva-kilbiṣaiḥ
bhuñjate te tv agham pāpā
ya pacanty ātma-kāraṇāt
"The devotees of the Lord are released from all kinds of sins because they eat food which is first offered for sacrifice. Others, who prepare food for personal sense enjoyment, verily eatonly sin." All food is given to us by the Supreme Personality of Godhead. Eko bahūnāṁ yo vidadhāti kāmān: the Lord supplies everyone with the necessities of life. Therefore we should acknowledge His mercy by performing yajña (sacrifice). This is the duty of everyone. Indeed, the sole purpose of life is to perform yajña.
(Srimad Bhagavatam----5:26:18----purport).

In animal life, eating, sleeping, sexual enjoyment and fear cannot be regulated, but for human society the plan is that although men, like animals, must be allowed toeat, sleep, enjoy sex and take protection from fear, they must be regulated. The Vedic plan for eating recommends that one take yajña-śiṣṭa, or prasāda, food offered to Kṛṣṇa. Yajña-śiṣṭāśinaḥ santo mucyante sarva-kilbiṣaiḥ: "The devotees of the Lord are released from all kinds of sins because they eat food that is offered first for sacrifice." (B.G.3:13) In material life, one commits sinful activities, especially in eating, and because of sinful activities one is condemned by nature's laws to accept another body, which is imposed as punishment.
(Srimad Bhagavatam----7:13:26----purport).

The gṛhastha should not eat anything not offered to the Supreme Personality of Godhead. As it is said in the Bhagavad-gītā (3.13), yajña-śiṣṭāśinaḥ santo mucyante sarva-kilbiṣaiḥ: "The devotees of the Lord are released from all kinds of sins because they eat food that is offered first for sacrifice." The gṛhastha should also visit the holy places of pilgrimage mentioned in the purāṇas. In this way he should fully engage in worshiping the Supreme Personality of Godhead for the benefit of his family, his society, his country, and humanity at large.
(Srimad Bhagavatam---7:14--summary).

Since the holy name and Kṛṣṇa are nondifferent, the members of the Kṛṣṇa consciousness movement not only chant the holy name of the Lord offenselessly, but also do not allow their tongues to eat anything that is not first offered to the Supreme Personality of Godhead. The Supreme Lord declares:
patraṁ puṣpaṁ phalaṁ toyaṁ yo me bhaktyā prayacchati
tad ahaṁ bhakty-upahṛtaṁ aśnāmi prayatātmanaḥ
"If one offers Me with love and devotion a leaf, a flower, a fruit or water, I will accept it." (B.G.9:26) Therefore the International Society for Krishna Consciousness has many temples all over the world, and in each and every temple the Lord is offered these foods. On the basis of His demands, the devotees chant the holy name of the Lord offenselessly and never eat anything that is not first offered to the Lord. The functions of the tongue in devotional service are to chant the Hare Kṛṣṇa mahā-mantra and eat prasādam that is offered to the Lord.
(Sri Caitanya Caritamrta----1:8:16----purport).

The word upakaraṇa indicates a variety of foods, such as dhal, vegetables and other varieties of possible dishes that one can eat very nicely with rice. It is not proper, however, for a sannyāsī to eat such palatable dishes. If he did so, he would not be able to control his senses. Śrī Caitanya Mahāprabhu did not encourage sannyāsīs to eat very palatable dishes, for the whole Vaiṣṇava cult is vairāgya-vidyā, as renounced as possible. Caitanya Mahāprabhu also advised Raghunātha dāsa Gosvāmī not to eat very palatable dishes, wear very nice garments or talk on mundane subjects. These things are all prohibited for those in the renounced order. A devotee does not accept anything to eat that is not first offered to Kṛṣṇa. All the rich foods offered to Kṛṣṇa are given to the gṛhasthas, the householders. There are many nice things offered to Kṛṣṇa—garlands, bedsteads, nice ornaments, nice food and even nicely prepared pan, betel nuts-but a humble Vaiṣṇava, thinking his body material and nasty, does not accept such preparations for himself. He thinks that by accepting such things he will offend the lotus feet of the Lord. Those who are sahajiyās cannot understand what Śrī Caitanya Mahāprabhu meant when He asked Advaita Ācārya to bring two separate leaves and give a small quantity of the prasādam to Him.
(Sri Caitanya Caritamrta----2:3:70----purport).

Śrīla Bhaktivinoda Ṭhākura says, tāra madhye jihvā ati, lobhamaya sudurmati. Among the senses, the tongue is the most formidable enemy of the conditioned soul. Urged by the tongue, one commits many sinful activities. Although Kṛṣṇa has given human beings nice food, people still commit sins by killing poor animals for the satisfaction of the tongue. Not being able to control the tongue, the conditioned soul eats more than he needs. Of course, everyone must eat to keep the body fit for the Lord's service, but when one cannot control the senses, he falls victim to the dictations of the tongue and the belly. Naturally, genital agitation follows, and one seeks illicit sex. However, if one is fixed at the lotus feet of Kṛṣṇa, he can control the tongue. Bhaktivinoda Ṭhākura further states, kṛṣṇa baḍa dayāmaya, karibāre jihvā jaya, sva-prasāda-anna dilā bhāi: in order to conquer the tongue, Kṛṣṇa has been very merciful and has given us nice food that has been offered to Him. When a person is attached to Kṛṣṇa's lotus feet, he does not eat anything not offered to Kṛṣṇa. Sei annāmṛta khāo, rādhā-kṛṣṇa-guṇa gāo, preme ḍāka caitanya-nitāi. Since a devotee eats only prasādam, he conquers the dictations of the tongue, belly and genitals. One can control the dictates of the senses when situated in the position of śānta-rasa. Then one's advancement in Kṛṣṇa consciousness is assured.
(Sri Caitanya Caritamrta----2:19:213----purport).

The first impediment is atyāhāra, overeating or accumulating more wealth than we need. When we give free rein to the senses in an effort to enjoy to the highest degree, we become degraded. A devotee should therefore eat only enough to maintain his body and soul together; he should not allow his tongue unrestricted license to eatanything and everything it likes. The Bhagavad-gītā and the great ācāryas, or spiritual masters, have prescribed certain foods for human beings, and one who eats these foods eats in the mode of goodness. These foods include grains, fruits, vegetables, milk products, and sugar—and nothing more. A devotee does not eat extravagantly; he simply eats what he offers to the Supreme Lord, Kṛṣṇa. He is interested in kṛṣṇa-prasādam (food offered to the Lord) and not in satisfying his tongue. Therefore he does not desire anything extraordinary to eat.
(Narada Bhakti Sutra).