Periodic fasting has been discussed on this list as
a way of mimicking the circumstances of fluctuating
food supplies that our paleo ancestors would have
faced from time to time.  One health benefit of fasting
seems to be a priming of the insulin receptors, see
article below.  Partly as a consequence of the better
insulin sensitivity, it is my understanding that another
health benefit of fasting is a surge in the production of
hgh that supposedly happens in the first few days of
a fast.  Does anybody know of any information that
confirms this?

Peter

http://abcnews.go.com/wire/Living/ap20030429_228.html

Regular Fasting Seems to Improve Health

Regular Fasting Seems to Improve Health As Much As
Cutting Calories The Associated Press

WASHINGTON April 29

The health benefits of sharply cutting calories may occur
after periodic fasting, even if the fast does not result in eating
less overall, a new report indicates.

Scientists are now planning a study to see if fasting, which
seems to benefit mice, will also be good for people too.
Benefits ranging from longer life to less stress and greater
sensitivity to insulin have been reported in recent studies of
severe reductions in diet.  But mice that were fed only every
other day, but were allowed to gorge themselves on the days
they ate, had similar health benefits to ones on a diet reduced
by 40 percent of normal food intake, a team of researchers
reports in Tuesday's online edition of Proceedings of the
National Academy of Sciences.

While the cause of health improvements from cutting back
on diet isn't fully understood, many researchers had assumed
that a long-term reduction in calories was involved.
The new study by Mark Mattson and colleagues at the
National Institute on Aging found equal benefits, however,
for mice that ate only every other day, even if they didn't
cut total calories, because they ate twice as much on days
they weren't fasting.  Mattson said a study is being planned to
test the effect of fasting on people. The plan is to compare
the health of a group of people fed the normal three meals
a day with a similar group, eating the same diet and amount
of food, but consuming it within four hours and then fasting for
20 hours before eating again. that a lot of children are overweight.
It's still unclear the best way to somehow get people to eat
less," Mattson said.
"One possibility is skipping a meal a day. Our study suggests
that skipping meals is not bad for you."

Dr. Carol Braunschweig of the University of Illinois at
Chicago, who as not part of the study team, said she was
intrigued by the suggestion that a drastic change in eating
patterns might have benefits.  "With the current epidemic of
obesity and physical inactivity facing the U.S. today, identification
of a beneficial eating pattern that could address some of the
untoward effects of excess weight would be a very significant
finding," she said.  Mattson said an earlier study found that mice
that fasted every other day had extended life spans. The new
experiment found the mice also did better in factors involved in
diabetes and nerve damage in the brain similar to Alzheimer's
disease, he said.
"We think what happens is going without food imposes a mild
stress on cells, and cells respond by increasing their ability to
cope with more severe stress," Mattson said. "It's sort of
analogous to physical effects of exercise on muscle cells."
He said the researchers think this stress occurs throughout
the body, which might be the reason fasting seems to
increase life span and the animals become more resistant
to the diseases of aging.  The dieting mice consumed 40 percent
less food than mice eating normally and lost nearly half their body
weight (49 percent) in the experiment, while the fasting mice
weighed only a little less than mice eating normally.

In recent years, some nutritionists have recommended eating
smaller amounts more often, but this study did not deal with
that type of eating pattern.
In the new report, the researchers said both the fasting mice
and those on a restricted diet had concentrations of blood
sugar and insulin that were significantly lower than mice allowed
to eat whenever they wanted. Indeed, insulin levels in the fasting
mice were even a bit lower than the dieting ones.

At the end of the experiment all three groups of mice were
injected with a toxin that damages cells in the part of the
brain called the hippocampus. Cell damage there is involved
in Alzheimer's in humans.  When the mouse brains were later
analyzed the scientists found that the brains of the fasting mice
were more resistant to damage by the toxin than the brains of
either dieting mice or those eating normally.

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