Yoga simply means union. In Indian tradition it means union with supreme reality. What is the way to find this union? Do not go for extremes, find the middle path – Shri Krishna in the sixth Chapter of Srimad Bhagwat Geeta, on importance of middle path in Yoga:
नात्यश्नतस्तु योगोऽस्ति न चैकान्तमनश्नतः ।
न चाति स्वप्नशीलस्य जाग्रतो नैव चार्जुन ॥
Verily, yoga is not for him who eats too much or abstains too much from eating. It is not for him, O Arjuna, who sleeps too much or keeps awake too much. We must be free from animal cravings. We must avoid excess in all things.
Compare with this the middle path of the Buddha, the golden mean of Aristotle.