To be in sync with nature is to put oneself in perfect harmony with universe. All are one. Yin and yang working in perfection. Not too much one way or the other. This also applies to ourselves. We must we seek discipline of mind and body. Many people fixate on body and ignore needs of mind. Some cultivate mind but ignore needs of body. Feeding mind and starving body most unwise as feeding body and starving mind. Seek proper balance in nourishing self.
To cultivate the mind, body, and spirit, balance yin and yang. If people understood this simple concept, world peace and universal harmony would naturally arise. You do not need to worry about understanding and harmonizing and making all things one. Universe is already a harmonious oneness, we usually just do not realize it. Keep the polarities balanced and walk in harmony.