Doctor Chung,
I found the following information in another newsgroup and it reminded
me of your fast. Since you a doctor, you probably already knew this
information but in case you do not--I posted it below. If your fast
has already ended, disregard this post.
Jason
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

http://www.drlowe.com/QandA/askdrlowe/thymetab.htm

Under certain conditions, the conversion of T4 to T3 decreases, and
more reverse T3 is produced from T4. Three of these conditions are food
deprivation (as during FASTING or starvation), illness (such as liver
disease), and stresses that increase the blood level of the stress
hormone called cortisol. We assume that reduced conversion of T4 to T3
under such conditions slows metabolism and aids survival.

Thus, during FASTING, disease, or stress, the conversion of T4 to
reverse-T3 increases. At these times, conversion of T4 to T3 decreases
about 50%, and conversion of T4 to reverse-T3 increases about 50%.
Under normal, non-stressful conditions, different enzymes convert some
T4 to T3 and some to reverse-T3. The same is true during fasting,
illness, or stress; only the percentages change--less T4 is converted
to T3 and more is converted to reverse-T3.

The reduced T3 level that occurs during illness, FASTING, or stress
slows the metabolism of many tissues. Because of the slowed metabolism,
the body does not eliminate reverse-T3 as rapidly as usual. The slowed
elimination from the body allows the reverse-T3 level in the blood to
increase considerably.

In addition, during stressful experiences such as surgery and combat,
the amount of the stress hormone cortisol increases. The increase
inhibits conversion of T4 to T3; conversion of T4 to reverse-T3
increases. The same inhibition occurs when a patient has Cushing's
syndrome, a disease in which the adrenal glands produce too much
cortisol. Inhibition also occurs when a patient begins taking cortisol
as a medication such as prednisone. However, whether the increased
circulating cortisol occurs from stress, Cushing's syndrome, or taking
prednisone, the inhibition of T4 to T3 conversion is temporary. It
seldom lasts for more than one-to-three weeks, even if the circulating
cortisol level continues to be high. Studies have documented that the
inhibition is temporary.