Suzanne,

Welcome to the group :) Many people in this group know about Fast-5 as
a weight loss regimen, and may not be aware of the expected benefits
of intermittent fasting (IF), so I'll put in this little explanatory
blurb:

Fast-5 qualifies as a way of practicing intermittent fasting. In
recent animal studies, forms of IF have been shown to prolong life,
reduce cancer risk, and diminish or eliminate symptoms of inflammatory
diseases. The exact duration of fasting that delivers these benefits
is unknown.

Now, back to your question...

Sleep is important in that it seems to reset the body's instinctive
drive to eat (called "limbic hunger" in the book) and promote a high
level of willpower to resist eating until break-fast. Having the
eating window late in the day simply allows less time after the eating
window closes when one must choose not to eat even though food is
available and the fast has been broken for the day. The 5-10pm window
was also intended to allow for snacking as part of evening relaxation
and entertainment, whether it be TV, movies, a party, or whatever.

There is no data I know of that indicates what the minimum time of
fasting is that delivers the benefits of intermittent fasting seen in
animal studies. Most of the animal studies have a full day of fasting
followed by a full day of ad-lib eating, which delivers about 36 hours
of very low insulin levels in a 48-hour period. Having a five-hour
daily window delivers about the same period of very low insulin
levels, but there is no formal proof that the two are equal in terms
of fasting benefit. My personal experience and anecdotal reports from
people using the Fast-5 schedule indicate that at least some of the
benefits of intermittent fasting (IF) are provided by the Fast-5
schedule. These reports are highly subjective, and may be purely
coincidental, but include anti-inflammatory effects with reduced
symptoms of arthritis, asthma, and allergies, as well as improvement
in other markers such as lower cholesterol, blood pressure, and
fasting glucose levels.

Moving the window to 1-6 pm should have no impact on the benefits of
fasting, since the 19-hour fasting period remains intact. It *may* be
more difficult to close one's window at 6 pm and resist eating until
bedtime, but that depends greatly on the individual and his/her
schedule and evening routine. The earliest window I know of in
successful long-term use is 3-8pm. I believe others out there have
tried 1-6, but I do not have feedback from them to relay to you. (If
you're out there reading this, please reply.)

I hope you find this helpful and that you find some application of IF
that works well for you. Please let us know here or by email how it
works best for you.

Bert

Bert Herring
Fast-5 LLC

--- In fast5@yahoogroups.com, "organicmission" <drbuffie@...> wrote:
>
> Hi,
> I found this group through researching intermittent fasting (15 hour
> fasting period). I was wondering if anyone has any experience with
> changing the eating window to say 1-6pm. I read the downloadable book,
> but all I caught was that it was important to sleep during the first
> part of your fast - not why it was important- or if it would still be
> effective if you changed the window.
> Thanks-
> Suzanne
>