You go through childhood with such innocence.  The body grows along the way and changes.  It does this by itself.  You need make no effort and you grow taller and fill out.  The body continues to renew itself moment by moment, cell by cell.  Why would the spirit not also continuously grow?  That is life:  constant growth.  You as spirit are also constantly changing.  That is why you exist. 
 
The body goes from small to large.  The spirit increases in vibration.  The higher vibration reflects a more loving soul, for love is the highest of all vibrations.  You stunt your physical growth by poisoning the body with toxic substances and lack of exercise.  You stunt the spirit body by absorbing and giving off the lower vibrations of judgment, hate, and anger. 
 
How tall do you wish to grow?  Ingest a daily diet of loving kindness.  Shower it freely upon others and bring full health to the human-spirit body.  It is a team effort.