Ad libitum, abbreviated as ad lib, is Latin for 'at pleasure,' meaning it
is given freely and without restriction.  An ad libitum diet is one that
a ferret can freely access at any time.  Leave a food dish in a ferret's
cage and keep it filled with kibble, and your ferret is consuming an ad
lib diet.  A considerable mythology has recently developed suggesting
ferrets require an ad libitum diet for optimal health, even to the point
that it is oft repeated in ferret-oriented magazines and books.  It has
even been repeated by veterinarians.
 
When discussing the nutritional needs of an ill ferret, an ad libitum
diet MAY be appropriate.  However, extensive research encompassing dozens
of species suggest such a diet has been extensively linked to shorter
life spans, and either initiates, promotes, or exacerbates a plethora of
diseases, ranging from various organ disease (skin, brain, eyes, heart,
liver, pancreas, intestines, immune system), to various cancer and
tumors, to epilepsy, to generalized early ageing, to obesity and
obesity-related disease.  This research dates back to the 1920s, but has
been largely overlooked for a number of reasons, not the least being it
is hard to obtain funding to extend animal lifespan when most become a
McDonalds menu item before their second birthday.  Only when funds became
available to study questions of extending human lifespan did major
investigations of the phenomenon begin.
 
A glance at the proffered bibliography shows this question is not some
sort of weak hunch published in obscure journals.  The papers listed are
found in the top scientific journals available, all extensively reviewed
by skeptical experts.  This is as mainstream as science gets!  Read these
quotes:
 
"Calorie restriction (CR) is arguably the best-documented and most potent
experimental manipulation for decreasing tumor development ... and
increasing longevity ...."
 
"Calorie restriction (CR) is a well-documented and highly effective
experimental manipulation for suppressing tumor development, suppressing
autoimmunity, and extending lifespan ..."
 
"Calorie restriction ... attenuates [limits] autoimmune renal disease
and delays age-related Sjogren's-like lesions in salivary glands while
increasing life span ...."
 
"Dietary restriction is the only reproducible method for extending the
life span ...."
 
"Dietary restriction (DR) has been shown to slow the rate of
physiological decline and the development of age-associated diseases ...
and to extend life span ...."
 
"Dietary restriction attenuates inflammatory responses to myocardial
ischemia-reperfusion injury."
 
"Chronic calorie restriction (CR) without malnutrition remains the only
robust means of increasing life span and delaying the onset of a wide
range of age-related diseases and physiological changes ...."
 
"In laboratory animals, dietary restriction prolongs life span, improves
physiologic function, and prevents or lessens severity of several
diseases including ... inflammatory states."
 
"Dietary restriction is acknowledged to prolong life span...improve
declining physiologic functions ... prevent or lessen severity of
spontaneously occurring, chemically induced, and radiation-induced
neoplasia, and autoimmune diseases ... protect against ozone-induced lung
inflammation, and alleviate chemically induced ulcerative dermatitis."
 
"Caloric restriction (CR) involves underfeeding and has long been
recognized as a dietary therapy that improves health and increases
longevity."
 
"Calorie restriction modulates age-dependent changes in the retinas of
brown Norway rats."
 
"Animals kept on such a diet [CR] are prone to less disease and are
generally healthier."
 
"Moderate dietary restriction has long been recognized as a natural
therapy that improves health, promotes longevity, and reduces both the
incidence and growth of many tumour types."
 
"... AL [ad libitum] feeding of [sedentary caged animals] is a form of
over feeding that can produce adverse health effects."
 
"Dietary restriction reduces angiogenesis and growth in an orthotopic
mouse brain tumour model."
 
I purposely included this large number of quotes to show that not only
was the negative effect of an ad libitum diet well known, but that it was
well-known to a large number of scientists specializing in diverse fields
of study.  I could have easily filled several FMLs with similar quotes; I
copied 73 journal articles for this review, read another 20 or so online,
and borrowed about a dozen books (one with 40 pages of references).
These comments are universal.
 
Bob C
 
[NModerator's note: Do you realize that all this talk about food is
getting me hungry?  Damn.  BIG]
[Posted in FML issue 3950]