viviktasevee laghvaashee yatavaakkaayamaanasaha |
dhyaanayogaparo nityam vairaagyam samupaashritaha || 52 ||

One who stays in seclusion, eats very little, regulates speech, body and mind, considers meditation as supreme, fully possessed of dispassion.
viviktasevee : staying in seclusion
laghvaashee : eating very little
yatavaakkaayamaanasaha : regulating speech, body and mind
dhyaanayogaparaha : to whom meditation is considered supreme
nityam : ever
vairaagyam : dispassion
samupaashritaha : fully possessed
Shri Krishna continues describing the lifestyle of a sanyaasi, a monk or a renunciate, which is a recap of ideas covered in the sixth chapter. He says that such a monk like places that are vivikta, meaning isolated, solitary, away from the hustle and bustle of daily life. Such places are conducive for contemplation, since they do not have too many distractions. He is also laghvaashee, eating only the quantity of nutritious food necessary to sustain the body. Eating heavy meals causes drowsiness in the short term, and health problems in the long term.
Now even if the mind is placed in quiet surroundings, it will generate thoughts that will eventually result in actions of the body, or in speech. By regulating physical actions and speech, the monk will be able to regulate his mind as well. The end result of all this regulation is two fold. He will be able to fix his mind on the self, which is dhyaana, and will be able to contemplate upon the nature of the self, which is yoga. The nature of the self was expounded in the second chapter to be infinite, indestructible and so on.
The quality of dispassion or vairagyam comes up again in this shloka. In the last shloka, it was implicitly mentioned as absence of raaha and dvesha, like and dislike. The level of vairagya cultivated by the monk, however, is much greater than that which is harboured by seekers in early stages of spiritual practice. The monk has rid himself of even a tinge of belief that there is any real happiness to be found in the material world. He is samupaashritaha, fully possessed of the conviction that the self alone is worth pursuing, nothing else.