When the soul undergoes development, it then experiences all the sugar it takes into its body, or already has within it, as something giving it inner firmness, supporting it inwardly, permeating it to a certain extent with a sort of natural sense of selfhood. And in this respect a sort of eulogy might even be pronounced on sugar. In passing through a soul development a person may even often notice that he needs to take sugar, because the psychic development inevitably tends to make him become more and more selfless. Through an orderly anthroposophical development the soul of itself becomes more selfless. […] 

It might be said that, through eating sugar, a sort of blameless ego-sense is produced, forming a counterpoise to the necessary selflessness in the spiritual realm of morals. Otherwise there might all too easily be the temptation not only to become selfless, but also dreamy and fantastic, to lose the healthy capacity for judging earthly conditions. An addition of sugar to the food gives the power, in spite of the ascent into the spiritual world, to stand firmly on the earth with both feet, and to cultivate a healthy estimate of earthly things. [ …] 

On the whole, we may say the consumption of sugar intensifies physically the character of the human personality. We may be so certain of this that we may even say that it is easier for those who take sugar to imprint the character of their personality upon their physical body than for those who do not; but it stands to reason that this must be kept within healthy limits.

Source: Rudolf Steiner – GA 145 – Effects of Occult Development: Lecture II – The Hague – March 21, 1913