SB 10.10.16

nityaṁ kṣut-kṣāma-dehasya
 daridrasyānna-kāṅkṣiṇaḥ
indriyāṇy anuśuṣyanti
 hiṁsāpi vinivartate
Synonyms: 
nityam — always; kṣut — with hunger; kṣāma — weak, without necessary strength; dehasya — of the body of a poor man; daridrasya — poverty-stricken; anna-kāṅkṣiṇaḥ — always desiring to get sufficient food; indriyāṇi — the senses, which are compared to snakes; anuśuṣyanti — gradually become weaker and weaker, with less potency; hiṁsā api — the tendency to be envious of others; vinivartate — reduces.
Translation: 
Always hungry, longing for sufficient food, a poverty-stricken man gradually becomes weaker and weaker. Having no extra potency, his senses are automatically pacified. A poverty-stricken man, therefore, is unable to perform harmful, envious activities. In other words, such a man automatically gains the results of the austerities and penances adopted voluntarily by saintly persons.
Purport: 

According to the opinion of experienced medical practitioners, diabetes is a result of voracious eating, and tuberculosis is a disease of undereating. We should desire neither to be diabetic nor to be tubercular. Yāvad artha-prayojanam. We should eat frugally and keep the body fit for advancing in Kṛṣṇa consciousness. As recommended elsewhere in Śrīmad-Bhāgavatam (1.2.10):

kāmasya nendriya-prītir
 lābho jīveta yāvatā
jīvasya tattva-jijñāsā
 nārtho yaś ceha karmabhiḥ

The real business of human life is to keep oneself fit for advancement in spiritual realization. Human life is not meant for making the senses unnecessarily strong so that one suffers from disease and one increases in an envious, fighting spirit. In this Age of Kali, however, human civilization is so misled that people are unnecessarily increasing in economic development, and as a result they are opening more and more slaughterhouses, liquor shops and brothels. In this way, the whole civilization is being spoiled.