Our body is functioning on 96 principles. Out of 96, we get only 20 princiiples through food, and probably more to 30 those who do Yogic practice. Deficit close to 60.
To balance this rest of 60, you need to practice Dhyan Yoga. Only in Dhyan, you get fresh flow of Cosmic Prana which will work in your body. Rest of the time when your mind, senses, breath engaged in external activities, this Cosmic Prana wont flow in you.
Once you get and balance this deficit 60 principles = your body automatically becomes Kayakalpa.