Srimad-Bhagavatam: Canto 11 - Chapter 1 - Verse 43
Sanskrit:
योगं निषेवतो नित्यं कायश्चेत् कल्पतामियात् ।तच्छ्रद्दध्यान्न मतिमान्योगमुत्सृज्य मत्पर: ॥ ४३ ॥
ITRANS:
yogaṁ niṣevato nityaṁkāyaś cet kalpatām iyāttac chraddadhyān na matimānyogam utsṛjya mat-paraḥ
Translation:
Although the physical body may be improved by various processes of yoga, an intelligent person who has dedicated his life to Me does not place his faith in the prospect of perfecting his physical body through yoga, and in fact he gives up such procedures.
Purport:
A devotee of the Lord keeps his body fit by eating nourishing Kṛṣṇa prasādam, by maintaining a clean and regulated life, free from unnecessary anxiety, and by chanting and dancing before the Deity of the Lord. When a devotee is sick, he accepts medical treatment by normal methods, but beyond this there is no need to absorb one’s mind in the physical body in the name of so-called yoga practice. Ultimately one must accept the destiny that has been ordained by the Lord.