Prabhupada's lecture - Śrīmad-Bhāgavatam 1.3.14 - Los Angeles, September 19, 1972
So the idea is that there is no food problem. As the mother earth said to King Pṛthu that "I am restricting," so the more you become sinful, the food supply will be stopped. This is the law of nature. At the end there will be no foodgrains, at the end of Kali-yuga. That is stated in the Śrīmad-Bhāgavatam. There will be no foodgrain, no fruits, no milk, no sugar. You have to live on flesh and blood.
At that time, being hungry, you will kill your own children and eat flesh and blood. That day is waiting. So this is the civilization. Most heinous civilization. It can only be saved by spreading this Kṛṣṇa consciousness movement. Otherwise there is no way.