Most people who practice regularly find that it holds them to their correct weight, but basically the true yogi follows a diet that does not introduce too much waste matter into the body. Moderation is the keynote of yogi's diet, and it means cutting down on all waste producing drinks and foods that put a strain on the body's system, draining energy from the mind and body.
One of the first things to understand is that food is needed primarily to build up and maintain the body, but by about the age of 25 growth stops, ageing begins and only maintenance is needed. If the body is loaded with excess food or the wrong food, it will degenerate and age prematurely. Therefore food should be eaten in the right quantity and with the right quality to keep the body in a state of optimum health and with the right quality to keep the body in a state of optimum health and balance. If you east an excess of animal fats and proteins, ageing begins much faster.
To realize God, a sound body and mind are essential. The body is a sacred temple and the mind controls the body. The sole, your true self, which is conscious and luminous of itself, given expression through the mind-body instrument. When the mind and body are purified of restricting mental and physical characteristics, the light of the sole can be self-revealed.
Fasting helps in keeping the body in an optimum state of health. Saints and monks of every order have used fasting with prayer and meditation to reach higher spiritual states of consciousness. Others have it as a practice to improve their physical and mental health, while natural therapists recommend fasting as a basic of curing many diseases.
There is a difference between fasting and starving. Fasting is undertaken for religious or spiritual purposes, or to regain bodily health by detoxifying the body. It is giving up food when there is no real hunger, to eliminate toxins and poisons that the body's system has accumulated, and to allow nature to do its work of healing. In fact, the point where the body starts to starve because it is important to realize that the fasting stage only takes place so long as the body can support itself on the fasting stage only takes place so long as the body can support itself on the stored reserves with in the body.
Fasting helps in removing toxins and poisons from the body, assisting in eliminating disease so that one can regain perfect health. Fasting is nature's own doctor.
By fasting, prana in the body is vivified and the life-spark rekindled. Fasting purifies the pranamaya kosha (the vital sheath) and makes the mind serene and tranquil. It purifies the mind and takes one away from the body/ego-consciousness into the spiritual awareness and consciousness of the self. The mood for prayer and meditation comes easily during a fast and the body feels lighter.
When there is no food being digested, body can concentrate fully on what is already there. The build-up of waste materials is more effectively expelled via the bowels, kidneys, skin and lungs, purifying the blood.
Fast of over one week not only cleanse the body but vivify one with more energy, power and spiritual strength. the will-power and concentration are developed, and one's energies are thoroughly recouped. the body become firmed and the skin clearer, and the eyes sparkle like a baby's. The mind, insight and thoughts become clearer.
The vedic scriptures points out that fasting helps one to control the mind and senses, so that one can advance in spiritual realization.