Answer to Question 1
Potassium is found in muscle in high concentrations and is necessary for muscle contraction and heart function. Potassium can be lost easily with the increased urinary excretion that occurs with such fasts and, with restricted intake, potassium may be restricted also.
Answer to Question 2
Caffeine would act as a diuretic and cause water-soluble vitamins and some minerals to be lost along with the loss of fluids. Usually, no more than one glass of caffeine-containing fluids is allowed per day.