(Click to enlarge painting of foods in the three modes of nature—goodness, passion and ignorance)
"One's bodily luster and beauty, one's constitution, one's activities and one's qualities all depend on the law of cause and effect. There are three qualities in material nature, and as stated in the Bhagavad-gītā (13.22), kāraṇaṁ guṇa-saṅgo 'sya sad-asad-yoni-janmasu: one takes birth in a good or bad family according to his previous association with the qualities of material nature. Therefore one seriously eager to achieve transcendental perfection, Kṛṣṇa consciousness, must eat Kṛṣṇa prasāda. Such food is sāttvika, or in the material quality of goodness, but when offered to Kṛṣṇa it becomes transcendental. Our Kṛṣṇa consciousness movement distributes Kṛṣṇa prasāda, and those who eat such transcendental food are sure to become devotees of the Lord. This is a very scientific method, as stated in this verse from Nala-naiṣadha (3.17): kāryaṁ nidānād dhi guṇān adhīte. If in all one's activities he strictly adheres to the mode of goodness, he will certainly develop his dormant Kṛṣṇa consciousness and ultimately become a pure devotee of Lord Kṛṣṇa.
Unfortunately at the present moment the bodily constitutions of the leaders of society, especially the governmental leaders, are polluted. As described in Śrīmad-Bhāgavatam (12.1.40):
prajās te bhakṣayiṣyanti
Such leaders have no chance to purify their eating. Politicians meet together and exchange good wishes by drinking liquor, which is so polluted and sinful that naturally drunkards and meat-eaters develop a degraded mentality in the mode of ignorance. The processes of eating in different modes are explained in the Bhagavad-gītā, wherein it is stated that those who eat rice, wheat, vegetables, milk products, fruit and sugar are situated in the elevated quality of goodness. Therefore if we want a happy and tranquil political situation, we must select leaders who eat Kṛṣṇa prasāda. Otherwise the leaders will eat meat and drink wine, and thus they will be asaṁskṛtāḥ, unreformed, and kriyā-hīnāḥ, devoid of spiritual behavior. In other words, they will be mlecchas and yavanas, or men who are unclean in their habits. Through taxation, such men exploit the citizens as much as possible, and in this way they devour the citizens of the state instead of benefiting them. We therefore cannot expect a government to be efficient if it is headed by such unclean mlecchas and yavanas."
(Caitanya-caritāmṛta Antya 1.92, Purport)