According to Osho, the paradox is that the more you identify with the body, the more unconscious enmity you carry toward it—expressed as indulgent decay or ascetic torture; but as identification drops through meditation, hostility falls and a natural friendliness arises. In witnessing you choose the middle-string tuning—neither tight nor loose—caring for the body as a sacred instrument rather than exploiting or punishing it.
When you stop clinging to the body and just watch, you stop fighting it and start caring for it gently, avoiding extremes.