Abstract
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Dietary restriction has been shown to have several health benefits including
increased insulin sensitivity, stress resistance, reduced morbidity, and
increased life span. The mechanism remains unknown, but the need for a long-term
reduction in caloric intake to achieve these benefits has been assumed. We
report that when C57BL/6 mice are maintained on an intermittent fasting
(alternate-day fasting) dietary-restriction regimen their overall food intake is
not decreased and their body weight is maintained. Nevertheless, intermittent
fasting resulted in beneficial effects that met or exceeded those of caloric
restriction including reduced serum glucose and insulin levels and increased
resistance of neurons in the brain to excitotoxic stress. Intermittent fasting
therefore has beneficial effects on glucose regulation and neuronal resistance
to injury in these mice that are independent of caloric intake.

Introduction
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Aging refers to the biological changes that occur during a lifetime that result
in reduced resistance to stress, increased vulnerability to disease, and an
increased probability of death. The rate at which aging occurs is
species-specific, suggesting a strong genetic influence. The only environmental
variable that has been shown to markedly affect the rate of aging in a wide
range of species is caloric intake: Restricting food intake to a level below
that which would be consumed voluntarily results in a decrease in the rate of
aging and an increase in average and maximum life span (1, 2). Dietary
restriction (DR) reduces cancer formation (3, 4) and kidney disease (5) and
increases the resistance of neurons to dysfunction and degeneration in
experimental models of Alzheimer's and Parkinson's diseases as well as stroke
(6–9). Two different DR paradigms have proven effective in increasing life span
and disease resistance in rats and mice. In one paradigm animals are provided a
daily food allotment that is typically 30–40% less than the ad libitum (AL)
consumption of a control population; this limited daily feeding (LDF) paradigm
involves a controlled caloric restriction and a corresponding reduction in body
weight. In the second paradigm animals are subjected to intermittent
(alternate-day) fasting (IF), which in rats results in reduced food intake over
time and decreased body weight (10).

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This full paper, provided by Christopher, about mice on intermittent fasting
regimens can be viewed at:
http://snipurl.com/4d7w
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