You are advised to consult the books Kemetic Diet by Muata Ashby and the book Joy of Juicing by Gary Null
Fasting should be done regularly for general health.
It is not recommended to be done specifically for the purpose of “forcing” and hereby expecting altered states of consciousness that are sometimes later confused with “spiritual” experiences. Also it is advised to avoid severe fasting that can hurt the physical body. These two aberrations lead to respectively, medal imbalances and physical imbalances that are counterproductive in the pursuit of Nehast. Maat is balance and though intensity should increase in spiritual practice, that intensity should remain in balance so as to maintain clarity.
It does not serve if a car can accelerate to a high speed but then shakes apart. So too the physical and psycho-spiritual constitution of the aspirant should develop tolerances that exceed ordinary human capacities but in order, balance and clarity, avoiding (not specifically pursuing) delusions and distractions like anomalous sounds, headaches, colors, astral projections, communing with dead souls or stirring cosmic forces they are not prepared to experience. If such experiences arise in the course of spiritual practice, whether sought or unsought, these should be observed passively and witnessed with a perspective of admiring the vastness and complexity of Creation and the varied planes of existence but refraining from engaging with them or believing in their reality as anything other than further expressions of the fleeting nature of Creation as witnessed by dualistic mind.
The witnessing practice in this way renders the experiences devoid of having the capacity to distract or entangle the personality, again, allowing it the freedom to pursue and discover and experience the absolute and transcendental nature of Spirit, which is beyond any and all qualifications, visions or mental expressions.