All demigods serve as the limbs to Lord Kṛṣṇa. All how to satisfy the demigods is already mentioned in the vedas. But Srila Prabhupada also tells that if you just water the root of the plant, all branches and leaves will automatically get water. In the same way, devotees of Lord Krishna directly worship the Supreme Personality of Godhead, the master of all demigods. By serving Kṛṣṇa, all demigods automatically gets satisfied. Therefore the devotee of the Lord only eat the remnants of the food offered to lord known as prasadam. Whenever an epidemic disease arise in the state or country, an antiseptic is given which protects us from it, in the similar way, when a devotee honours the prasadam ( food offered to Lord Viṣṇu), he gets protected from all material contamination. Material world is a place full of contamination. On the contrary, those who are karmis or gross materialists who eat food without offering it to Lord Kṛṣṇa, keeps on increasing their sinful activities ultimately preparing themselves for the body of hogs and dogs in their next lives. Everyone is directly-indirectly dependent on the food grains. Even meat eaters who eat animals are also indirectly dependent on grains in order to eat such animals. And food grains are produced by rains which is under the control of the demigods such as Indra, Chandra, Surya, etc. and they showers rain when the Supreme Lord is satisfied. And Lord Kṛṣṇa is satisfied by performance of the yajñas. If you don't perform sacrifices, you will have scarcity and that is the law of nature. In the Kaliyuga, Harinam Sankirtan is considered as the greatest sacrifice and by performing so, you will be saved atleast from the scarcity of food.
