CC Antya 6.226

vairāgīra kṛtya — sadā nāma-saṅkīrtana
śāka-patra-phala-mūle udara-bharaṇa
Word for word: 
vairāgīra — of a person in the renounced order; kṛtya — duty; sadā — always; nāma-saṅkīrtana — chanting the holy name of the Lord; śāka — vegetables; patra — leaves; phala — fruit; mūle — by roots; udara-bharaṇa — filling the belly.
Translation: 
“The duty of a person in the renounced order is to chant the Hare Kṛṣṇa mantra always. He should satisfy his belly with whatever vegetables, leaves, fruits and roots are available.