The World Turned Upside Down: The Second Low-Carbohydrate Revolution by Richard David Feinman Page A
Authors: Richard David Feinman
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it would be more fattening but, in fact,
people
rarely put more than 100 kcal (tablespoon) on the bread (typically 100
kcal/slice). How fattening food is depends on how much you eat, so the
suggestion that you reduce fat because of its caloric density only
makes sense
if you don't replace it with anything, that is, reduce the calories.
Fat is the most calorically dense
food but
caloric density, like
any density, can be very misleading – density is a measure per amount
of
material or per unit volume, or per gram, per something, so it matters how much of something that you have. Calories
per gram
is not informative unless you know how many grams. Things like caloric
density
or any density for that matter are measures of intensity ,
and technically these
measurements are called intensive
variables. Intensive variables are
independent of mass: one
tablespoon of butter has the same energy density (kilocalories per gram) as two tablespoons of butter, but obviously two
tablespoons has twice the total calories – total calories measures the
amount that you have.
Such measurements are called extensive
variables . Extensive variables depend on how
much you have, not
the character of the substance. It is the same as the old (updated)
riddle:
which is heavier? A pound of uranium or a pound of styrofoam? Of course
they
are the same. A pound is a pound. Uranium has an extremely high density
(about
1.6 times that of lead) so a pound of uranium is only a little bigger
than a
major league baseball but you would have to fill up the room with
styrofoam to
equal the same pound.
Fraction, or percent is another kind
of
measure of intensity that
can be misleading. Looking ahead, this is one reason that
recommendations on
percent of increase in risk that is always reported in the media is
usually
meaningless: your odds of winning the lottery are increased by 100 %,
that is,
doubled, by buying two tickets instead of one. Does that make you want
to play?
Bottom line: when you hear people say that fat has more calories per
grams, you
know that is irrelevant. You have to know how many grams you are
actually
eating.
The Obesity Epidemic
The
Obesity Epidemic
So, what did we eat during the past
thirty
or forty years? What
kind of macronutrients were in our diet? You may know this better than
our
students who probably did not attend to the problem.
3. During the epidemic of
obesity and diabetes, the macronutrient that increased most was:
__ X _ Carbohydrate.
_____ Protein.
_____ Fat.
_____ All about the same. Calories
increased across the board.
Student
Performance on Question 3
Many students know at this point
where I
am coming from and there
are probably more votes for carbohydrate than if this were the first
question.
However, many people, students included, still think that calories were
increased across the board. The epidemic of obesity and diabetes has
been
accompanied by a substantial de crease
in the percent fat and, at least for men, the absolute amount also went
down
slightly.
Figure 2-2 shows data from the National Health and Nutrition Examination Survey
(NHANES)
which is conducted at the intervals listed in the horizontal axis. The
vertical
axis is the absolute amount of calories consumed and the large increase
in energy
consumed appears to be due entirely to a dramatic increase in the
consumption
of carbohydrate. The percent change shown along the top indicates the
expected
decrease in fat but, at least for men, the absolute amount of fat
(total
calories) and, notably, the absolute amount of saturated fat went down.
There is a lot of error in these
kinds of
surveys but it is
pretty much excluded that there was any increase in fat intake. It is also likely that
if obesity and
diabetes had gotten better, it would have been attributed to the
significant
fall in saturated fat consumption. The clearest conclusion is that an
increase
in carbohydrate consumption compared to fat is associated with greater
total
intake and that a
people
rarely put more than 100 kcal (tablespoon) on the bread (typically 100
kcal/slice). How fattening food is depends on how much you eat, so the
suggestion that you reduce fat because of its caloric density only
makes sense
if you don't replace it with anything, that is, reduce the calories.
Fat is the most calorically dense
food but
caloric density, like
any density, can be very misleading – density is a measure per amount
of
material or per unit volume, or per gram, per something, so it matters how much of something that you have. Calories
per gram
is not informative unless you know how many grams. Things like caloric
density
or any density for that matter are measures of intensity ,
and technically these
measurements are called intensive
variables. Intensive variables are
independent of mass: one
tablespoon of butter has the same energy density (kilocalories per gram) as two tablespoons of butter, but obviously two
tablespoons has twice the total calories – total calories measures the
amount that you have.
Such measurements are called extensive
variables . Extensive variables depend on how
much you have, not
the character of the substance. It is the same as the old (updated)
riddle:
which is heavier? A pound of uranium or a pound of styrofoam? Of course
they
are the same. A pound is a pound. Uranium has an extremely high density
(about
1.6 times that of lead) so a pound of uranium is only a little bigger
than a
major league baseball but you would have to fill up the room with
styrofoam to
equal the same pound.
Fraction, or percent is another kind
of
measure of intensity that
can be misleading. Looking ahead, this is one reason that
recommendations on
percent of increase in risk that is always reported in the media is
usually
meaningless: your odds of winning the lottery are increased by 100 %,
that is,
doubled, by buying two tickets instead of one. Does that make you want
to play?
Bottom line: when you hear people say that fat has more calories per
grams, you
know that is irrelevant. You have to know how many grams you are
actually
eating.
The Obesity Epidemic
The
Obesity Epidemic
So, what did we eat during the past
thirty
or forty years? What
kind of macronutrients were in our diet? You may know this better than
our
students who probably did not attend to the problem.
3. During the epidemic of
obesity and diabetes, the macronutrient that increased most was:
__ X _ Carbohydrate.
_____ Protein.
_____ Fat.
_____ All about the same. Calories
increased across the board.
Student
Performance on Question 3
Many students know at this point
where I
am coming from and there
are probably more votes for carbohydrate than if this were the first
question.
However, many people, students included, still think that calories were
increased across the board. The epidemic of obesity and diabetes has
been
accompanied by a substantial de crease
in the percent fat and, at least for men, the absolute amount also went
down
slightly.
Figure 2-2 shows data from the National Health and Nutrition Examination Survey
(NHANES)
which is conducted at the intervals listed in the horizontal axis. The
vertical
axis is the absolute amount of calories consumed and the large increase
in energy
consumed appears to be due entirely to a dramatic increase in the
consumption
of carbohydrate. The percent change shown along the top indicates the
expected
decrease in fat but, at least for men, the absolute amount of fat
(total
calories) and, notably, the absolute amount of saturated fat went down.
There is a lot of error in these
kinds of
surveys but it is
pretty much excluded that there was any increase in fat intake. It is also likely that
if obesity and
diabetes had gotten better, it would have been attributed to the
significant
fall in saturated fat consumption. The clearest conclusion is that an
increase
in carbohydrate consumption compared to fat is associated with greater
total
intake and that a
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