- Excerpt
SURVIVAL OF THE THINNEST:
How to Use Your Genetic Script
to Stay Thin Without Dieting
by David Hariton
INTRODUCTION
David Hariton's new book, Survival of the Thinnest, could
be the eight ounces that tips the scale against Atkins, a diet the author
argues is doomed to fail.
In fact, all diets are doomed, according to Hariton, because they fight
our genetic script. Hariton's book is based on meticulous research of
the medical literature regarding diet, exercise, and genetics. It also
contains an ingredient missing from almost all diet books: common sense.
In our diet-obsessed culture, however, the conclusion Hariton comes to
sounds radical: It doesn't matter what you eat -- or how much -- as long
as you practice a specific 30-minute routine every day.
The excerpt, below, explains why we get fat, and why dieting is incapable
of providing a meaningful weight-loss solution. More information about Survival
of the Thinnest and author David Hariton follows the excerpt.
Enjoy!
Fitting Into Your Genes
by David Hariton
Why is your body storing more and more fat?
Why is it doing this now, when it didn't do it before?
I am surprised at how rarely people who hope to lose weight speculate
about the forces that govern the shapes of their bodies. Why don't people
who want to be thinner start by asking themselves why they are not thin
right now? They take it for granted that they are no longer thin because
they have eaten too much and that becoming thin again is just a matter
of eating less. They view their bodies as passive depositories, like
piggy banks. Calories are deposited in the bank when food is consumed.
Calories are withdrawn from the bank as energy is expended. The excess
of their deposits over their withdrawals equals their fat accounts. To
reduce the balance of their fat accounts, they must deposit less, or
spend more, or both.
Forgive me, but this doesn't seem like a very thoughtful analysis. Your
body is not a passive fat depository. It is a life force that actively
controls and regulates every aspect of its physical existence. Your body
temperature similarly equals the excess of the heat energy you absorb
or create over the heat energy that you lose. But if you were running
a fever, you wouldn't walk naked through the snow in an effort to lower
your body temperature. You would call the doctor to find out why your
body had raised its temperature. You can't treat an undesirable symptom,
like the fact that there is too much fat on your body, by attacking it
directly. The symptom will only come back. You must deal with whatever
is causing the symptom. Then the symptom will go away by itself.
A great deal of evidence supports the conclusion that your body actively
maintains its levels of fat. If your body were just a passive fat depository,
then if you stayed on a diet you would get thinner and thinner until
you died of starvation, and if you never dieted, you would get fatter
and fatter until you became grossly obese.
Neither of these things happens.
Not to you, not even to little babies who are allowed to eat as much
as they want to and never get on a scale. Your body is not relying on
you to determine how much fat it should be storing, any more than it
is relying on you to determine how much muscle it should be maintaining,
or how many blood cells it should be circulating, or how many hormones
it should be secreting, or how much it should be growing and when it
should stop.
Rather, your body has a "lipostat" that
is set at a specific level of body fat, just as it has a thermostat
that is set at 98.6 degrees. Your body actively responds to any sustained
variation in caloric intake to maintain the levels of fat that it wants
to maintain. For example, your body reduces its metabolism in response
to a sustained reduction in caloric intake, and it increases its metabolism
in response to a sustained increase in caloric intake. Metabolism accounts
for 70% of an individual's daily caloric expenditure. Your long-term
appetite also increases in response to a loss of body fat and decreases
in response to an increase in body fat. Your body controls your long-term
appetite by varying the levels of appetite- suppressing chemicals,
such as leptin, that make you feel satiated even though your stomach
is empty. Your body also responds to a sustained reduction in caloric
intake by producing less thermal energy; discouraging physical activity;
increasing psychological interest in appetizing foods; and inducing
sensations of hunger in your esophagus and your stomach.
It doesn't take much for your body
to return its fat levels to where they're set. An energy imbalance
of 100 calories per day (the equivalent of an apple, or a light beer)
is enough to change your weight by ten pounds over the course of a
year. In fact, you are completely dependent on your body's "lipostat" to
maintain your levels of fat in the long run. How could you possibly
guess on your own the amount of caloric intake required to regulate
your levels of fat so precisely?
Why Can't You Fight Your Body With Diets?
How effective can it be to try to force your body to maintain lower
levels of fat than it wants to maintain by continually depriving it of
food? That is like trying to cool down your house by opening up the windows
while keeping the thermostat at 80 degrees. The heater will just respond
by producing more heat, and your house will get hot as soon as you close
the windows again. The mere fact that you have some short-term control
over the level of your fat deposits doesn't mean that your body isn't
maintaining them in the long run.
You are capable of lowering your body temperature in the short run.
But if you do, your body will use both physical and psychological means
to fight you. It will increase your metabolism, it will generate thermal
energy, it will make you shiver, it will make you feel cold, it will
make you fantasize about hot fires and warm baths. In the end, you will
lose the fight, no matter how determined you are.
Why should your experience be any different if you try to maintain lower
levels of fat than your body wants you to maintain? Won't it lower your
metabolism? Won't it make you feel sensations of hunger, in both your
esophagus and your stomach? Won't it make you fantasize about food? I'll
bet this has been your experience. I'll bet you gained back most of the
weight you lost on your most recent diet, and far sooner than you had
hoped. Conversely, the few times in your life when your weight really
shot up, I'll bet you had relatively little trouble losing a couple of
pounds.
Moreover, when you go on a diet, your body doesn't just consume its
stored fat. It also consumes some of its muscle. In effect it concludes
that you need to hold on to your fat, since fat is your most efficient
emergency food store, but you can do without some of that muscle that
you apparently aren't using. In terms of daily metabolism, muscle is
ten times more costly to maintain than fat. No wonder your starving body
keeps the fat and gets rid of the muscle. If you were forced to live
for 90 days without food, you might survive if your body consumed its
muscle first and its fat last, rather than the other way round. But once
it consumes its high-metabolism muscle, your body needs less energy to
maintain itself, and it becomes that much harder for you to stay thin.
In fact, if you remain sedentary but keep going on diets, you will actually
get fatter. Studies show that people who diet store more fat in the long
run than people who don't. This is not counter-intuitive. It makes perfect
sense. According to the body's logic, people who diet are in greater
danger of starvation and need to store more fat as insurance. Studies
similarly show that people who tend to dehydrate themselves retain more
water, and people who drink water all the time retain less. The body
assumes -- very logically -- that people who often become dehydrated
are living in places where water is frequently unavailable, and they
are therefore in greater danger of dying of thirst. How depressing for
people who try to stay thin by going on diets.
"But if all this is true," you ask, "why was I thin in college? Why
was I thinner even five years ago? Don't these facts indicate that my
body has no preference regarding how much fat I maintain, at least over
a certain range?" No they don't. What they indicate is that your body's
preferences have changed over time. What they indicate is that as you
have gotten older and more sedentary, your body has been trying to store
more fat. In Survival of the Thinnest, we figure out why.
Most of the changes in your own
physical form have occurred by design, rather than by default. If you "work out" or
take a job that forces you to lift heavy materials, for example, your
muscles increase in size. When you stop, their size decreases again.
Your body changes to suit your changing life circumstances.
At 20 you were thin, and your weight
didn't vary. What happened next? Did your body get lazy? Did it continue
to precisely regulate everything about your physical form, from the
size and shape of your muscles to the levels of sugar and hormones
in your blood, but when it came to your fat deposits, it suddenly threw
up its hands and said "whatever"?
That doesn't make any sense. Your body doesn't let your temperature
drift between 93 and 103 degrees. It doesn't randomly increase and decrease
your muscle tissue, depending on how much you eat. Your fat is body tissue.
Why would your body deal with it differently? To the contrary (as discussed
in Survival of the Thinnest), for most of the period during
which our genes were evolving, the level of our fat deposits was a matter
of life or death. It was essential for the body to maintain them at precise
and appropriate levels.
The logical conclusion is that your
body has been trying to store different amounts of fat at different
times in your life to suit different life circumstances. It follows
that the reason you are not thin today is not because you have been
eating too much. It is because you have been eating the right amount.
You are not "out of shape" in any objective sense.
You are in the shape that your body is actively trying to keep you in. "But
how can that be?" I can hear you say. "These love handles? These flabby
thighs? This ample rear end? This beer belly? I don't want these things.
My companion doesn't want them. Surely my body feels the same way." But
your body doesn't have feelings. Your body follows a genetic script.
How Can You Make Your Body Make You Thin?
Your body follows a genetic script.
And based on that script, your body is maintaining the size of your
love handles just as it maintains the size of your biceps. In following
its genetic script, your body does not distinguish among tissues. It
does not love your muscles and hate your fat. It maintains the body
that biological forces dictate that you should have. Of course you
know, from basic biology, that you have a complex genetic inheritance
that exists in every cell of your body and that determines almost everything
about your body, including the size of your fat deposits. But people
tend to have a very static conception of their genetic inheritances. "I got all the fat genes, and my sister
got all the thin genes," people are wont to say fatalistically. It would
be far more accurate to conceive of your genetic inheritance as a series
of formulas that direct your body to maintain different forms to suit
various life circumstances.
Consider your genetic inheritance
for muscle formation. Do you have "big
muscle genes" or "small muscle genes"? The answer, of course, is neither.
You have a genetic formula that directs your body to increase the size
of its muscles when you are lifting a lot of weight and decrease them
when you are not. Every mammal on the earth has a genetic inheritance
that causes it to adapt its form to suit its changing life circumstances.
Have human beings alone inherited forms that are immutable? Have human
beings survived and prospered through eons of evolution with bodies that
refuse to adapt to their changing life circumstances?
The form that your body is trying to maintain is therefore not determined
by your genes alone. It is determined by the interaction between your
genes and your life circumstances. Your genetic inheritance is directing
your body to store fat under some life circumstances and to stay thin
under other ones.
Now one thing we know is that you can't change your genetic inheritance.
Although Lamarck once hypothesized that the genes of a giraffe change
over time as the giraffe stretches its neck up into the trees to eat
leaves, this hypothesis was proven wrong by Charles Darwin. A giraffe
and its offspring will have the same genes, no matter how much they stretch
their necks. But you can change your life circumstances.
Giraffes do have genes that direct their bodies to maintain longer necks
if they stretch them often and shorter necks if they don't. Many of the
people I know are like Lamarck. They are convinced that if they keep
on dieting, their bodies will give up one day and just keep them thin.
But your body doesn't give up, because your genes never change. If you
want to stay thin, you're going to have to change your life circumstances
and keep them changed.
Fortunately, you can turn on your "active/thin" gene
with the minimum amount of time and effort, which means that you can
persuade your body that it can't afford to store fat without turning
your life upside down.
Copyright ©2004 by David Hariton. All rights
reserved. Reprinted here with permission. Please feel free to duplicate
or distribute this file, as long as the contents are not changed and
this copyright notice is intact.
