SB 7.15.18

santuṣṭaḥ kena vā rājan
 na vartetāpi vāriṇā
aupasthya-jaihvya-kārpaṇyād
 gṛha-pālāyate janaḥ
Word for word: 
santuṣṭaḥ — a person who is always self-satisfied; kena — why; vā — or; rājan — O King; na — not; varteta — should live (happily); api — even; vāriṇā — by drinking water; aupasthya — due to the genitals; jaihvya — and the tongue; kārpaṇyāt — because of a wretched or miserly condition; gṛha-pālāyate — he becomes exactly like a household dog; janaḥ — such a person.
Translation: 
My dear King, a self-satisfied person can be happy even with only drinking water. However, one who is driven by the senses, especially by the tongue and genitals, must accept the position of a household dog to satisfy his senses.
Purport: 

According to the śāstras, a brāhmaṇa, or a cultured person in Kṛṣṇa consciousness, will not enter anyone’s service to maintain body and soul together, and especially not for satisfaction of the senses. A true brāhmaṇa is always satisfied. Even if he has nothing to eat, he can drink a little water and be satisfied. This is only a matter of practice. Unfortunately, however, no one is educated in how to be satisfied in self-realization. As explained above, a devotee is always satisfied because he feels the presence of the Supersoul within his heart and thinks of Him twenty-four hours a day. That is real satisfaction. A devotee is never driven by the dictations of the tongue and genitals, and thus he is never victimized by the laws of material nature.