They are not completely separate Yogas, they are only different avenues of approach to accommodate the varying requirements of the growth process. The most visible aspect of Yoga, in the west, is called Hatha Yoga. This is the physical culture portion of Yoga which is just the foundation for the broader science called Raja Yoga. Body and Breath Physical exercise is accomplished through the practice of Hatha Yoga postures called Asanas which stretch the spine and tone the muscles and ligaments of the body. Relaxation exercises release tension and rest the body and the mind.
Conscious breathing leads to realizing the link between breathing patterns and mental activity.
Another portion of Raja Yoga is called Pranayama, the science of breath and energy control. Pranayama works with the life-force, Prana, that energizes the body and also links us with the mind. Pranayama, therefore, works between medicine and psychology. Through the conscious movement of prana we can establish the proper harmony between the body and the mind. The Sattvic diet , eating what is light, nourishing, well balanced and natural, is a part of Ayurvedic Dietary therapy developed primarily for the practice of Yoga.