Vegetables, grains, fruits, milk and water are the proper foods for human beings and are prescribed by Lord Kṛṣṇa Himself. Whatever else we eat cannot be offered to Him, since He will not accept it. Thus we cannot be acting on the level of loving devotion if we offer such foods.
(Bhagavad-Gita-----9:26-----purport).

Those who do not make an offering of their food, He says in the same verse, are eating only sin. In other words, their every mouthful is simply deepening their involvement in the complexities of material nature. But preparing nice, simple vegetable dishes, offering them before the picture or Deity of Lord Kṛṣṇa and bowing down and praying for Him to accept such a humble offering enables one to advance steadily in life, to purify the body, and to create fine brain tissues which will lead to clear thinking. Above all, the offering should be made with an attitude of love.
(Bhagavad-Gita-----9:26-----purport).

Without their help no living entity can live. So if one can understand that the light and splendor of the sun, moon and fire are emanating from the Supreme Personality of Godhead, Kṛṣṇa, then one's Kṛṣṇa consciousness will begin. By the moonshine, all the vegetables are nourished. The moonshine is so pleasing that people can easily understand that they are living by the mercy of the Supreme Personality of Godhead, Kṛṣṇa.
(Bhagavad-Gita-----15:12-----purport).

Were it not for Him, all the planets would scatter, like dust in air, and perish. Similarly, it is due to the Supreme Personality of Godhead that the moon nourishes allvegetables. Due to the moon's influence, the vegetables become delicious. Without the moonshine, the vegetables can neither grow nor taste succulent. Human society is working, living comfortably and enjoying food due to the supply from the Supreme Lord. Otherwise, mankind could not survive. The word rasātmakaḥ is very significant. Everything becomes palatable by the agency of the Supreme Lord through the influence of the moon.
(Bhagavad-Gita-----15:13-----purport).

The purpose of food is to increase the duration of life, purify the mind and aid bodily strength. This is its only purpose. In the past, great authorities selected those foods that best aid health and increase life's duration, such as milk products, sugar, rice, wheat, fruits and vegetables. These foods are very dear to those in the mode of goodness. Some other foods, such as baked corn and molasses, while not very palatable in themselves, can be made pleasant when mixed with milk or other foods. They are then in the mode of goodness.
(Bhagavad-Gita-----17:10-----purport).

The best food is the remnants of what is offered to the Supreme Personality of Godhead. In Bhagavad-gītā the Supreme Lord says that He accepts preparations ofvegetables, flour and milk when offered with devotion. Patraṁ puṣpaṁ phalaṁ toyam. Of course, devotion and love are the chief things which the Supreme Personality of Godhead accepts. But it is also mentioned that the prasādam should be prepared in a particular way.
(Bhagavad-Gita-----17:10-----purport).

The more we attempt to exploit material nature according to our whims of enjoyment, the more we shall become entrapped by the reaction of such exploitative attempts. If we have sufficient grains, fruits, vegetables and herbs, then what is the necessity of running a slaughterhouse and killing poor animals? A man need not kill an animal if he has sufficient grains and vegetables to eat. The flow of river waters fertilizes the fields, and there is more than what we need. Minerals are produced in the hills, and the jewels in the ocean.
(Srimad Bhagavatam----1:8:40-----purport).

The productive energy of the laborer is misused when he is occupied by industrial enterprises. Industry of various types cannot produce the essential needs of man, namely rice, wheat, grains, milk, fruits and vegetables. The production of machines and machine tools increases the artificial living fashion of a class of vested interests and keeps thousands of men in starvation and unrest. This should not be the standard of civilization.
(Srimad Bhagavatam----1:9:26-----purport).

Grains and vegetables can sumptuously feed a man and animals, and a fatty cow delivers enough milk to supply a man sumptuously with vigor and vitality. If there is enough milk, enough grains, enough fruit, enough cotton, enough silk and enough jewels, then why do the people need cinemas, houses of prostitution, slaughterhouses, etc.? What is the need of an artificial luxurious life of cinema, cars, radio, flesh and hotels? Has this civilization produced anything but quarreling individually and nationally? Has this civilization enhanced the cause of equality and fraternity by sending thousands of men into a hellish factory and the war fields at the whims of a particular man?
(Srimad Bhagavatam----1:10:4-----purport).

The control of the Lord is everywhere, and if the Lord is pleased, every part of nature will be pleased. The river will flow profusely to fertilize the land; the oceans will supply sufficient quantities of minerals, pearls and jewels; the forest will supply sufficient wood, drugs and vegetables, and the seasonal changes will effectively help produce fruits and flowers in profuse quantity. The artificial way of living depending on factories and tools can render so-called happiness only to a limited number at the cost of millions.
(Srimad Bhagavatam----1:10:5-----purport).