The World Turned Upside Down: The Second Low-Carbohydrate Revolution (25 page)

More on Behavior

The principle in behavioral
psychology is that the time to
reinforcement is more important than the quality of the reinforcer.
Taste and
mouth feel are so immediately reinforcing that probably only aversive
stimulation works well. One positive take on hunger and what it means
is that
feeling hungry may mean that your diet is working and that you are
really
losing weight and therefore might stop eating before satiation. However
encouraging that might be as a guide to action (or inaction), it
usually can't
compete well with even the smell of food. You need something strongly
negative.

One of the more effective regimens is
a diet strategy from
Dr. Allen Fay, a psychiatrist in New York. It works like this:

1. You
   pick an amount of weight you want to lose in the next week; you can
   pick zero
   but, of course, you can't go up.
   
2. You
   write a check for $2, 000 to the Republican National Committee (in my
   case) and
   give it to Dr. Fay.
   
3. If,
   at the end of the week, you haven't hit the target, he mails the check.
   

In some cases, Dr. Fay said, you
don't even need money. One
patient wrote a letter to a right-to-life organization, telling them
what a
great job they were doing. The thought that she would get on their
mailing list
as a supporter was sufficiently aversive to keep her on target. You
pick your
own threat, of course. Dr. Fay suggested the American Nazi Party but I
thought
that they would only buy those shabby uniforms whereas, from my
perspective,
the Republicans would do real damage. My relation to Dr. Fay is partly
professional (although he admits that there are people who are beyond
psychotherapy) and partly friend. For the technique to work, you must
be
distant enough from the person holding the check so that they will
actually
mail it, but close enough that you will not consider physical violence
if they
do.

Imagery can help...up to a point. A
major problem situation
for dieters is that they have eaten what they want and feel satisfied
but there
is still food on their plate and they pick at it until they feel sick.
My
approach, when I felt full, was to imagine spiders coming out of the
food. This
worked for a while but over time I noticed that I was losing my
distaste of
spiders. Eating has a very strong Pavlovian component. It is not nice
to fool
Mother Nature.

Exercise 

The only thing that people in
nutrition agree on is the
value of exercise. While it is not as important as diet for weight
loss, it
does interact with diet and has obvious benefit. One question is when
to have
meals in relation to exercise. Although outside my area of expertise
and likely
to be an individual thing, there is some good guidance in the following
old
joke.

The couple come to the doctor and
don't want to have any
more children but they don't want any artificial methods of birth
control. The
doctor recommends exercise.

Husband: Before or after?

Doctor: Instead of.

Summary.

Hunger is poorly defined or, at least
its relation to
behavior and physiology is not simple. We have a sensation which may be
tied to
any number of things, food availability, meal-time, or even a real need
for
nourishment. The description that encompasses all the different things
is that
it means you are in a situation in which you are used to eating. So, in
the
search for causes of eating, what you come up with may only be a
restatement of
the behavioral observations. Knowing that it is a feeling that doesn't
have to
be answered may be helpful. Reduction in appetite is a major feature of
carbohydrate restriction but the other end of weight loss is metabolic
efficiency and the widely cited, if poorly understood, laws of
thermodynamics.
I try to shed some light on that. Next chapter.

Chapter
14

"calorie is a calorie,"
Thermodynamics, and all that

"A calorie is a calorie"

Can you lose more weight on one diet
than another if they
have the same number of calories? The question is usually about a
low-carbohydrate diet where the so-called metabolic advantage promises
you that
cutting out carbs will lead to reduced efficiency in storing fat. Folks
go
crazy when you suggest it's true. Whenever a scientific paper presents
data
showing that such a thing really happens, showing that one (usually
low-carb)
diet, is more effective than another, somebody always jumps in to say
that it
is impossible, that it would violate the laws of thermodynamics. Like
the
cartoon characters who run out over the cliff and fall only when they
realize
that they are not on solid ground, somehow the data are expected to go
away
once thermodynamics is invoked.

Of course, the data can't violate the
laws of
thermodynamics. There is the possibility that the data really are
accurate and
that the critic doesn't get it. Thermodynamics, the physics of heat,
work and
energy, is a tough subject and it takes real
chutzpah
to jump in where many physicists fear to tread.

Thermodynamics, however, is
interesting. It has been
described as the first revolutionary science. You probably don't really
need it
to study nutrition but if you catch on to the basics, you will
understand
something that seems counter-intuitive to many people. It will explain
how you
get more bang for your nutritional buck, that is, how you lose more
weight per
calorie.

When you consider that the
fundamental unit in nutrition is
the calorie, a unit of energy, it seems likely that it would be worth
knowing
something about the physics of energy exchange.

Text box 14-1
.
Arnold
Sommerfeld was one of the great physicists in the development of
quantum
mechanics (theory of atomic structure). He was also generally
considered to be
an expert on most areas of physics. His take on thermodynamics:

The
first time I studied it, I thought that I understood it except for a
few minor
details.

The
second time I studied it, I thought that I didn't understand it except
for a
few minor details.

The third time I
studied it, I knew I didn't understand it but it didn't matter because
I
already knew how to use it.

Bottom Line on
Metabolic Advantage.

Here are the four big questions and
the answers. The rest of
the Chapter will explain and justify these conclusions.

1. Metabolic
   advantage or, a better term, energy efficiency, is not contradicted by
   any
   physical law. Thermodynamics, in fact, more or less predicts variable
   energy
   efficiency. The way it has been discussed in nutrition is incorrect and
   does
   not conform to the way chemical thermodynamics is normally used.
   
2. Arguments
   against metabolic advantage often rely on practical considerations: how
   small
   the effect is. At the same time, the same critics espouse the value of
   cumulative small effects, operative in diets where you explicitly
   control
   calories, where 50 calories a day is supposed to add up over a year. It
   doesn't. Metabolism doesn't work like that. Homeostatic (stabilizing)
   mechanisms compensate for simple changes in calories unless they are
   the right
   kind of calories and, in fact, the effects of different macronutrients
   can be
   dramatic. In any case, if there really is any change at all, that
   should be a
   call to find out how to maximize it, not toss it.
   
3. Even
   if you aren't sure it's ever been demonstrated, it makes sense to try
   to make
   it work for you since, from the scientific standpoint, it is possible
   and the
   payoff is great.
   
4. Several
   mechanisms, particularly substrate cycling and gluconeogenesis, are
   involved. Experimentally,
   inefficiencies in digestion and metabolic processing, the so-called
   thermic
   effect of feeding, contribute as well.
   

Where we are going.

Many people find metabolic advantage
counter-intuitive
because of the idea of energy conservation. I will explain the fallacy.
I will
present some of the data and then explain how it could happen in terms
of
biochemical mechanisms.

The data.

There are basically two kinds of diet
experiments. Some
clearly show energy balance and some clearly don't. On the one hand, if
you
take a normal person and keep them in a hospital room and feed them
constant
calories (top panel,
Figure 14-1
),
you will find
that "wide variations in the ratio of carbohydrate to fat do not alter
total
24-h energy need
[76]
,"
their weight will stay roughly
constant. The figure is an example of what is meant by "a calorie is a
calorie." Common enough. Frequently, experimentally, a calorie
is
a
calorie. It's the same in experiments comparing diets of different
macronutrient
composition. Two people who are roughly similar in age and health will
respond
similarly to two isocaloric (same calories) diets regardless of the
diet
composition (amount of fat, carbohydrate and protein). This means that
yes,
calories count. But, there are many exceptions.

Figure 14-1
.
Comparison of diets. Data from references
[30,
61]
.

The energy balance shown in the
figure is achieved by
biology, not the laws of thermodynamics. In those cases where
everything
balances out, it isn't physical laws but rather the unique
characteristics of
living systems that keep things constant (homeostasis). Big rule: in
biology,
almost everything is connected in feedback and homeostatic mechanisms
compensate for chemical changes. In view of this, we should be asking
"how
is energy balance possible when it is not predicted from
thermodynamics",
not "how could there be different weight gain or loss for the same
calories".
So let's look at the exceptions., the second type of diet experiment
seen in
the literature.

The exceptions can be dramatic.
Figure
9-2
.
Duplicated in t
he bottom
panels of
Figure 14-1
show results of a study from
the laboratory of Jeff Volek, then at the University of Connecticut. In
this
study, described previously in
Chapter
9
, there
were 40 overweight men and women with metabolic syndrome (high
triglycerides,
low HDL or at least two of several other factors). They were assigned
to one of
two
ad
libitum
diets, described previously, either a very low-carbohydrate ketogenic
diet
(VLCKD) designed to provide a distribution of macronutrients along the
following lines: %CHO:fat:protein = 12:59:28, or a low-fat diet (LFD)
with a
distribution %CHO:fat:protein = 56:24:20. The experiment lasted 12
weeks.
Although neither group was specifically told to reduce calories, both
groups
did show a spontaneous decrease in energy intake – it seems that if you
sign up
for a diet experiment you automatically eat less. It's worth mentioning
that
this is not always the way the experiment is set up – frequently the
low-carbohydrate
arm is allowed
ad lib
consumption of food as long as it conforms to low-carb but the low-fat
diet to
which it is to be compared explicitly regulates calories (e.g.,
[77]
). That the low-carb diet
usually wins tells you
something right off.

Figure
14-2
shows the dramatic
difference in performance between the VLCKD and the low-fat diet. Part
A
indicates the average effect: weight loss on the VLCKD group was
dramatically
better. In reading the medical literature, however, it is important to
ask about
individual performance, especially when you are comparing different
time
points. People are different. Nobody loses an average amount of weight.
People
in both groups lost weight but what is remarkable about the figure is
the
number of people on the low-carbohydrate diet who lost a lot of weight.
Half of
the people on the VLCKD lost more than the single best person on the
low-fat
diet.

Can you trust dietary
records?

Critics of this kind of experiment
say that it relies on
patient dietary records, which are known to be inaccurate. While this
is true,
such data are not
wildly
inaccurate. Values can be off by 20% not 50% and are unlikely to be the sole
cause
of the differences. Also, ketone bodies were measured so at least the
VLCKD
group did what they were told. More important, if the differences were
due to
inaccurate reporting of dietary intake, that is,  if the diets
were truly
different in caloric intake, the people on the VLCKD must have
over-reported
what they ate and the people on LFD must have under-reported what they
ate, or
both. From a practical standpoint, it might be encouraging to be on a
diet
where you think that you are eating more than you really are.

Low-carbohydrate diets almost always
win in a face-off with
low-fat diets. Establishment nutritionists take it as a win if there is
a tie
but you can do that for just so long. So if it is not just about the
calories,
where does thermodynamics really fit in? With the disclaimer in
Textbox 1
, I will give you a
rough idea about how it's
done in real biochemistry.

Thermodynamics

It is the physics of heat, work and
energy. The subject is
fundamentally down to earth. It's roots are in the attempt to find out
just how
efficient a steam engine you could build – thermodynamics comes from
the
industrial revolution where the efficiency of steam engines was a big
deal. In
weight loss, we are really asking how efficiently food is utilized. The
other
side of thermodynamics is that the methods are highly mathematical and
arcane,
even for scientists. Thermodynamics has been described as "the science
of
partial differential equations" which is not to everybody's taste. The
results,
however, give you very simple equations for predicting things.
Heavy-duty
theory and practical application. It's what people who do like
thermodynamics
like about it. That's the main theme of this book – science with direct
applicability. You get an equation that tells you whether you have a
good steam
engine or, in fact, whether your food is fattening.