1. As I recall, the topic first came up long ago in relation to getting
longer lifespans.

2. These studies are NOT studies on reducing overweight or reducing
obesity. Trim is fine. Trim usually improves health. The longevity
studies with caloric restriction actually take the individuals down to
an intake long term that almost just manages to be starvation level.
It's a very tricky thing to do.

Caloric restriction studies take the caloric intake down to BELOW
maintenance levels long term. (The body adjusts as long as starvation
levels are not reached and as long as the diet is very, very, very
carefully balanced.)

Individuals who are on these diets do not get just trim; instead they
tend to be extremely thin.

Sometimes getting quite thin is also done for other health reasons
after the fact, for example, the reduction in pressure from fat in
the abdomen can help some men with enlarged prostates to urinate, and
certainly there are those with circulatory problems and other woes
whose physicians want them thin. ***Even those people are NOT on the
strict level used for the caloric restriction studies done to see if
longevity can be altered, though.*** So far, that kind of extreme
approach seems to work best in certain invertebrates with very mixed
results in vertebrates.

3. There was a report on this in Science News, too, which came out
last night:
<http://www.sciencenews.org/index/generic/activity/view/id/343374/title/Low-cal_longevity_questioned>

That mentions in more detail that some malignancy rate reduction can
be seen individuals who begin caloric restriction early BUT those
individuals have problems, too, even when experts are designing the
diet:

QUOTE

None of the monkeys that were started on calorie restriction early
on has developed cancer, she notes, compared with six monkeys in the
standard-diet group.

But calorie restriction very early in life may come with risk. Some
monkeys started very early on calorie restriction developed diabetes,
even though they are far from obese, she says, and some show signs
that their immune systems might not be as good as those in the control
animals.

QUOTE

Decades of research have linked low-calorie diets with extended
survival, but a new report finds that rhesus monkeys on strict diets
don't live longer than their counterparts getting a standard diet.

END QUOTE

That is consistent with the mouse studies which also have very mixed
results. The whys for the mixed results are what need to be uncovered.
There are multiple possibilities from the levels of caloric
restriction, the balance and components of the diet, and more.

END QUOTE

4. Yes, being trim is often associated with high amounts of exercise
and study after study after study has found that staying active is at
or near the top of the list for being healthy.

What needs to be taken home from this is that although a number of
invertebrates benefit from such extreme diets with longer life spans,
the results with diets as extreme as those used in the longevity
studies are very mixed with multiple vertebrates, and there can be
downsides for vertebrates like increased risks of diabetes and damaged
immune systems beyond NOT being able to design such a diet to be safe
without experts creating the diet and constant monitoring, as well as
constant hunger and needing to learn to sew to get clothing that fits,
or even doing brain damage if the diet is not balanced right. Those
downsides might also be there for other mammals like ferrets.

Again, remember, these studies are NOT about just being trim, which
is known to usually be more healthy. The diets and weights in this
situation are much more extreme.

Sukie (not a vet)  Ferrets make the world a game.

Recommended ferret health links:
http://pets.groups.yahoo.com/group/ferrethealth/
http://ferrethealth.org/archive/
http://www.miamiferret.org/
http://www.ferrethealth.msu.edu/
http://www.ferretcongress.org/
http://www.trifl.org/index.shtml
http://homepage.mac.com/sukie/sukiesferretlinks.html
all ferret topics:
http://listserv.ferretmailinglist.org/archives/ferret-search.html

"All hail the procrastinators for they shall rule the world tomorrow."
(2010, Steve Crandall)

A nation is as free as the least within it.

[Posted in FML 7534]