Here’s an interesting quote by Hector Durville:

“Most methods that claim to give you maximum strength, success, happiness, or influence over others seem incomplete to us. They do not examine the human being as a whole. They do not study, in an ordered way, the connection between the three parts of our nature, nor do they show how essential the full development of each part is to give proper value to the other two.

Some methods focus only on the muscular side and propose extreme physical exercise as the path to strengthening the will. Others deal only with diet, recommending vegetables, cereals, or fruit. Still others concentrate exclusively on breathing techniques. All of them look only at the physical aspect, the organs of the machine, yet they know neither the foreman of the factory nor its director.

There are also those who seek to subdue the unconscious by suppressing the sexual instinct or all desire, aiming at a kind of Buddhist nirvana. Others concern themselves only with the higher faculties of the mind: attention, reflection, judgment, reasoning, will. None of these approaches considers the human being in full. And yet true balance can be achieved only through the steady and progressive development of all the parts that compose us, since each part both influences and depends on the others.

You may say, “The work you propose will be long and difficult. I will grow tired before I reach the end.” Remember this: what is being proposed is not an instant and complete transformation, which would be unrealistic, but a new direction for your life, something essential. This new direction will already grant you a large part of what you seek. Other paths might turn you into physical or moral caricatures, leading to failures more painful than any slow and careful progress, and leaving behind nothing but lasting despair.

The aim is the harmonious development of all parts of your being. There is no failure for the one who knows how to persevere and truly wants to reach the goal.

To develop the whole person, you must first care for the machinery of the organism. The body produces the nervous energy used by both the unconscious and conscious mind. Your body is like a factory where workers constantly create new products, ideas and feelings, while others repair and maintain the tools that make all of this possible.”