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Does Calorie Restriction Extend Lifespan?
The relationship between calorie restriction and longevity has
been a popular topic for quite some time now. Here are the facts
about this issue that you need to know.
Calorie restriction (CR) is where you reduce daily calories by
30% to 50% in order to slow down your metabolism. Part of the idea
behind CR is that if you slow down your metabolism you allegedly
slow down aging. The objective is to get very thin so that your
smaller body doesn’t need many calories any more.
The biological mechanisms of potential lifespan extension through
CR are not fully understood, but researchers say that in addition to
changes in metabolism it may also involve factors such as reduced
oxidative damage, improvements in insulin sensitivity, and reduction
of glycation.
Mouse studies on CR go back as far as 1935, monkey studies began
in the late 1980s, and humans have been experimenting with CR for
quite some time. So far, the results are clear on one thing:
restricting calories does increase lifespan in rodents and other
lower species (yeast, worms and flies).
Studies suggest the life of the laboratory rat is 25% longer
with CR, and even longer with aggressive CR. In primates and humans,
biomarkers of aging show signs of slower aging with CR. Many CR
proponents feel that these studies and results prove that CR extends
lifespan in humans.
The truth is, there's no direct experimental evidence that humans
will live longer from practicing CR. Due to the length of human
lifespans, we will not have the necessary data for at least another
generation, and perhaps multiple generations. Even then, it will still
be highly speculative whether CR will extend human life at all, and
if so, by how much.
Many experts are skepitical about calorie restriction. Jay Phelan,
a UCLA biologist, says: "There is no current evidence that lifelong
caloric restriction leads to increased lifespan in primates. It's
certainly tantalizing that things like blood pressure or heart rate
look as though they're a lot healthier, and I believe they are. Whether
or not this translates to a significantly increased lifespan, I don't
know. I predict that it doesn't."
While some CR proponents claim that they don't get hungry and cite
studies suggesting that hunger decreases during starvation, researchers
say that hunger remains a big problem during CR, and that alone makes
CR impractical.
Personally speaking, the CR advocates that I've seen don't look very
fit or healthy. They're gaunt and have very little muscle mass. Until
more is learned about the relationship between calorie restriction and
longevity, I won't consider making it a part of my lifestyle.
Recommended Resource
Fit Over 40 contains plenty of information,
advice and motivation that can help anyone over 40 get fit and healthy and
slow down the aging process.
Read my review of Fit Over 40
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