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25th April 2009
Calorie Restriction for Life Extension:
What They Didn't Tell You on Oprah
On a recent episode of the Oprah show, one of
the guests was a 51 year old man with the heart of a 20 year old. He's been
following a calorie restriction plan and they said he might be one of the first
people to reach 120 years old by following this plan. There have been stories
both in the lay press and scientific press about calorie restriction for years
and it has been a frequent talk show topic on other many other TV shows.
However, before you cut your calories in half in hopes of adding another decade
onto your life, you'd better get the other half of the story they didn't talk
about on Oprah.
I’ve seen a lot of strange things in the health
field, and although calorie restriction (CR) is the subject of serious and
legitimate scientific study, I consider CR to be one of those strange things. Of
course, that’s because I choose a different lifestyle - the muscle-friendly
Burn The fat, Feed The Muscle
lifestyle - but there’s more than one reason why I’m not a CR advocate:
Hunger while dieting is almost always a challenge.
There’s some hunger even with conservative calorie deficits of 15-20% under
maintenance. Prolonged hunger is one of the biggest reasons people fall off the
weight loss diet wagon because it’s unpleasant and difficult to resist. This is
why pharmaceutical and supplement companies spend millions of dollars on
researching, developing and marketing appetite suppressants. Yet CR advocates
put themselves through 30-50% calorie restriction on a daily basis as a way of
life in the hopes of extending life span or health.
Practitioners of CR follow a low-calorie lifestyle,
but technically, they are not in a chronic 30% calorie deficit. That would be
impossible. What happens is their metabolisms get very slow (that’s part of the
idea behind CR; if you slow down your metabolism, you allegedly slow down
aging). So a 6 foot tall man who would normally require nearly 3,000 calories to
maintain his weight, might eventually reach an energy balance at only 1800 or
1900 calories. This is not just due to a ‘starvation mode’ phenomenon, that’s
only part of it. It’s primarily because he loses weight until he is very thin
and his smaller body doesn’t need many calories any more.
Does caloric restriction really extend lifespan?
The biological mechanisms of lifespan extension
through calorie restriction are not fully understood, but researchers say it may
involve alterations in energy metabolism (as mentioned above), reduced oxidative
damage, improvements in insulin sensitivity, reduction of glycation, modulation
of protein metabolism, downregulation of pro-inflammatory genes and functional
changes in both neuroendocrine and autonomic nervous systems.
Mouse studies on CR go back as far as 1935 and
monkey studies began in the late 1980’s. So far the results are clear on one
thing: caloric restriction 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 (even longer with aggressive CR). Primate
studies are still underway and humans have been experimenting with CR for some
time. In primates and humans, biomarkers of aging show signs of slower aging
with CR. This makes many proponents talk about this CR as if it were a
sure-thing, already proven through double-blind randomized clinical human
trials.
The truth is, there is NO direct experimental
evidence that you will live longer from practicing CR. Due to the length of
human life spans, 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 how much. We can
only estimate. I’ve seen guesses in the scientific literature ranging from 3 to
13 years, if CR is practiced for an entire adult lifetime.
Jay Phelan, a biologist at UCLA is skeptical. He
says the potential life extension is on the lower end of that range and the
increase is so small that it’s not worth the semi-starvation:
“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
are 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.”
I don’t quibble qualitatively with their
results. Yes, it will increase lifespan, but it will not increase it by 50% or
60%, it won’t increase it by 20% or 10%, it might increase it by 2%. So if you
tell me that I have to do something horrible for every day of my life for a 2%
benefit - for an extra year of life - I say no thanks.”
Is prolonged caloric restriction unhealthy?
When caloric restriction is practiced with optimal
nutrition (CRON), it is not inherently unhealthy. Actually, it appears the
reverse is true. First, the weight loss that comes with the low calories
produces improvements in the health markers, as you would expect. Second, the
meticulous choice of food from CRON practitioners, where they pick high nutrient
foods and avoid empty calories means that they are making healthy food choices.
Third, advocates say that the CR itself improves health. I wonder, however, how
much does CR improve health independent of the weight loss and the optimal
nutrition?
By losing fat and maintaining an ideal body
composition (the fat to muscle ratio) and eating high nutrient density foods, I
propose that even at a more normal caloric intake, you will get very significant
health and longevity benefits. I also propose that gaining muscle in a natural
way (no steroids) will increase your quality of life today and as you get older.
Aside from the fact that we are not lab rats, the
truth is, none of us knows when our day will come. We could get plucked off this
physical plane at any moment and have no control over how it happens. My belief
is that we should make our lifestyle decisions based on quality of life, not
just quantity of life. That includes our quality of life today as well as our
anticipated quality of life when we are older. Maybe we ought to be focusing
more on “health span” than life span.
Downsides of calorie restriction for life extension
One fact about calorie restriction that they often
don’t mention on these talk shows is that the benefits of CR decline if you
start CR at a later age. This was discussed in a research paper from the Journal
of Nutrition called, “Starving for life: what animal studies can and cannot tell
us about the use of caloric restriction to prolong human lifespan.” The author
of the paper, John Speakman from the School of Biological Sciences at the
University of Aberdeen in Scotland, said that the later in life you begin to
practice CR, the less of an increase in lifespan you will achieve. Even if the
CR proponents are right, if you started in your late 40’s or mid 50’s for
example, the benefit would be minimal. If you started in your 60’s the effect
would be almost nonexistent. Essentially, you have to “starve for life” to get
the benefits.
While some CR proponents claim that they aren’t
hungry and they cite studies suggesting that hunger decreases during starvation,
Speakman and other researchers say that hunger remains a big problem during CR -
especially in today’s modern society where we are surrounded with convenience
food and numerous eating cues - and that alone makes CR impractical:
“Neuroendocrine profiles support the idea that
animals under CR are continuously hungry. The feasibility of restricting intake
in humans for many decades is questionable.”
Let’s suppose for a moment that CR is totally legit
and the claims are true. Many of the proposed benefits of CR come at the expense
of what many of us are trying to do here: gain and maintain lean body mass. One
spokesman for CR is 6 feet tall and 130 pounds. Another poster boy for CR is 6
foot tall and 115 lbs. Measurements of rodents under CR not only show large
reductions in skeletal muscle but also bone mass.
I am not suggesting that these CR practitioners are
anorexic, a concern that has been raised about CR when practiced aggressively.
However, they are losing large amounts of fat-free tissue and that is plainly
obvious for all to see when you look at their bony physiques. I am not imposing
my body standards on others, but 115 to 130 lbs at 6 foot tall is underweight
for a man by any standard. Furthermore, researchers say that at the body mass
indices sustained by most voluntary CR practitioners, we would expect females to
become amenorrheic. “One thing that is completely incompatible with a CR
lifestyle is reproduction” says Speakman.
With that kind of atrophy, I have to wonder what
their quality of life will be like in old age. While many people struggle with
body fat for most of their adult lives, I’m sure almost everyone knows an
elderly person who wrestles with the opposite problem: they are seriously
underweight and they struggle to eat enough and maintain lean body mass.
My grandmother, before she passed away, was under
80 lbs. We could not get her to eat. She was weak and very frail. I have
reported many times about the research showing how most overweight people under
estimate calorie intake and eat more than they think or admit. In elder care
homes, the research has often showed the opposite - the patients over estimate
how much they eat. They swear they are eating enough, but they arent and they
keep losing dangerous amounts of weight. With underweight, atrophied seniors,
weakness means less functionality and lower quality of life and a fall can mean
more than broken bones, it can be life-threatening.
Life extension with more muscle
While there is a commonality between CRON and the
way I recommend eating (high nutrient density, low calorie density foods), in
most regards, CR is the opposite of my approach. In my
Burn The Fat, Feed The Muscle
program, we go for a higher energy flux nutrition program, which means that
because we are weight training and doing cardio and leading a very active
lifestyle, we get to eat more. Because we are so active and well-trained, the
eating more does not have a negative effect as it would on a sedentary person,
who might get sick and fat from the additional calories. We active folks take
those calories, burn them for energy, partition them into lean muscle tissue and
we enjoy a faster metabolism and extremely high quality of life.
As a bodybuilder, CR is not compatible with my
priorities, but hypothetically speaking, if I were to practice a lower calorie
lifestyle, I wouldn’t follow an aggressive CR approach. I’d probably do as the
Okinawans do. They have a very simple philosophy: hari hachi bu: eat until you
are only 80% full. While this does not mean there is a carefully measured 20%
calorie deficit, it’s consistent with what we practice in the
Burn The Fat, Feed The Muscle
lifestyle for a fat loss phase, and avoiding overeating is certainly a smart way
to avoid obesity and health problems. Incidentally, the Okinawans eat about 40%
less than Americans, and 11% less than they should, according to standard
caloric intake guidelines, and they live 4 years longer than Americans.
If someone is being “sold” on CR by an enthusiastic
CR spokesperson, or simply curious after watching the latest TV talk show (where
they are looking for controversial stories), it’s important to know that there
is more than one side to the story. If you carefully read the entire body of
research on CR, you will see that the experts are split right down the middle in
their opinions about whether CR will really work. CR for humans remains highly
controversial and there are no guarantees that this will extend your life.
Researchers at the National Institutes of Health in
Baltimore, MD put it this way:
“Because it is unlikely that an experimental
study will ever be designed to address this question in humans, we respond that
“we think we will never know for sure.” We suggest that debate of this question
is clearly an academic exercise.”
In closing, let me go back to one of the original
questions I was asked: “Can the BFFM food plan also be thought as a longevity
lifestyle, but with more muscle mass?” Absolutely beautifully said! That’s
precisely what Burn The Fat,
Feed The Muscle is.
I believe that by making healthy food choices but
doing so at a higher level of calorie intake and expenditure, that we can fend
off sarcopenia - the age related decline in muscle mass that debilitates many
seniors - while enjoying a more muscular physique, greater strength, and a less
restrictive lifestyle. Most gerontologists agree - by making simple lifestyle
changes that include strength training and good nutrition, you can easily turn
back the biological clock 10 years without going hungry.
For more information about Burn The Fat, Feed The
Muscle, the “longevity lifestyle with more muscle”, visit:
www.BurnTheFat.com
Train hard and expect success,
Tom Venuto
Fat Loss Coach
www.BurnTheFat.com
About the Author:
Tom Venuto is a fat loss expert, lifetime natural (steroid-free)
bodybuilder, independent nutrition researcher, freelance writer, and author
of the #1 best selling diet e-book,
Burn The Fat, Feed The Muscle: Fat-Burning Secrets of The World’s Best
Bodybuilders & Fitness Models (e-book) which teaches you how to get
lean without drugs or supplements using secrets of the world's best
bodybuilders and fitness models. Learn how to get rid of stubborn fat and
increase your metabolism by visiting: www.burnthefat.com
References:
Hunger does not diminish over time in mice under protracted
caloric restriction. Hambly C, Mercer JG, Speakman JR.Rejuvenation Res. 2007
Dec;10(4):533-42.Aberdeen Centre for Energy Regulation and Obesity (ACERO),
Rowett Research Institute, Bucksburn, Aberdeen, Scotland, United Kingdom.
Starving for life: what animal studies can and cannot tell us
about the use of caloric restriction to prolong human lifespan.Speakman JR,
Hambly C. J Nutr. 2007 Apr;137(4):1078-86. School of Biological Sciences,
University of Aberdeen, Aberdeen AB24 2TZ, Scotland, UK.
Can dietary restriction increase longevity in all species,
particularly in human beings? Introduction to a debate among experts. Le Bourg
E, Rattan SI. Biogerontology. 2006 Jun;7(3):123-5.
The potential for dietary restriction to increase longevity in
humans: extrapolation from monkey studies. Ingram DK, Roth GS, Lane MA, Ottinger
MA, Zou S, de Cabo R, Mattison JA.Biogerontology. 2006 Jun;7(3):143-8.
Laboratory of Experimental Gerontology, Intramural Research Program, National
Institute on Aging, National Institutes of Health, 5600 Nathan Shock Drive,
Baltimore, MD 21224, USA.
Caloric restriction in humans: potential pitfalls and health
concerns. Dirks AJ, Leeuwenburgh C.Mech Ageing Dev. 2006 Jan;127(1):1-7. Epub
2005 Oct 13, Wingate University, School of Pharmacy, 316 N. Main Street,
Wingate, NC 28174, USA.
Caloric restriction and human longevity: what can we learn
from the Okinawans? D. Craig Willcox, Bradley J. Willcox Hidemi Todoriki.
Biogerontology (2006) 7: 173—177
Endocrine alterations in response to calorie restriction in
humans. Mol Cell Endocrinol. 2009 Feb 5;299(1):129-36. Epub 2008 Oct 21. Redman
LM, Ravussin E. Pennington Biomedical Research Center, 6400 Perkins Road, Baton
Rouge, LA 70808, United States.
Caloric restriction in the presence of attractive food cues:
external cues, eating, and weight. Polivy J, Herman CP, Coelho JS.Physiol Behav.
2008 Aug 6;94(5):729-33. Epub 2008 Apr 13. University of Toronto, Canada.
Life Extension by Calorie Restriction in Humans. Everitt AV,
Le Couteur DG.Ann N Y Acad Sci. 2007 Aug 23, Centre for Education and Research
on Ageing, University of Sydney, Concord, New South Wales, Australia.
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