This section is from the book "The Hygienic System: Fasting And Sun Bathing", by Herbert M. Shelton. Also available from Amazon: The Hygienic System Vol III Fasting and Sun Bathing.
This is one of the fundamental organic functions which Morgulis states is improved by fasting. The remarkable effects of fasting upon the breathing of asthmatics can be really appreciated only by those who have watched it in many cases.
During the fast the excretion of carbon dioxide decreases. During the first stage of the fast the amount of carbon dioxide produced grows steadily less as the fast progresses, until the fasting level for metabolism is reached. This is due to decreased activity and lowered metabolism, and not to any lessening of the efficiency of the excretory function of the lungs. The breath is exceedingly foul; so much so at times that one can hardly remain in the same room with the patient.