health fitness

The human body must produce large amounts of energy for all
physical and mental activities. With proper balance between health
and fitness, the body will have no trouble meeting the energy require￾ments for optimal human performance. But where does this energy
come from? The answer is both simple and complex. Basically, ener￾gy comes from the sun. Light energy from the sun comes to earth and
is converted to chemical energy in plants through the process of pho￾tosynthesis. We eat the plants, and most of us eat animals that eat
plants. The chemical energy we take in is converted to mechanical
energy that fuels all our physical and mental activities.
More directly, the energy produced by the body comes from the
foods we eat. This energy is obtained from the basic macronutrients
in food — carbohydrate, fat and protein. Though many foods contain
all three, there’s usually a predominance of one of these in each food.
Consider the following examples:
• Carbohydrates are predominant in bread, sugar, rice,
pasta, fruit and fruit juice, cereal.
• Fats are dominant in oil, butter, cheese, egg yolk.
• Protein is highest in meat, fish, poultry, eggs, cheese.
The majority of energy is produced from two of these food groups
— carbohydrate and fat. Only a small amount, up to 15 percent of
total energy, is produced from protein (by conversion of certain amino
acids into glucose).
All three macronutrients are converted into energy in two steps.
First, they are broken down in the intestine and absorbed into the
blood as glucose from carbohydrates, fatty acids from fats, and amino
acids from protein.

In the second step, the blood ultimately carries these elements to
the cells, where the molecules of glucose, fatty acids and amino acids
are further broken down. The hydrogen atom, the common building
block of all three, is released as a result of further chemical break￾down. This atom contains one electron that is highly charged with
energy. This electron is finally converted to a substance called ATP,
which the body uses as energy.
So, to get more specific, we could say the body’s energy comes
from hydrogen’s electron. Carbohydrates, fats and proteins each have
different amounts of hydrogen molecules, and, therefore, potential
energy. Fats have by far the most hydrogen, one reason we can get
much more energy from the fats in food. Fats can actually provide
more than twice the potential energy you get from either carbohy￾drates or protein.
Where does all this energy-generating activity take place? Mostly
it is produced by your metabolism in the cells, especially in aerobic
muscle fibers, which primarily use fat as a fuel. When these muscles
are functioning optimally, you can derive even more energy from fat.
In fact, up to 90 percent of your energy at any given time can come
from fat, and the energy supply is virtually endless — the average
lean person has enough stored fat to endure a 1,000-mile trek!
The more energy you derive from fat the better your fitness,
health and human performance. By improving your fat-burning sys￾tem, you’ll improve metabolic efficiency and have more physical and
mental energy. In addition, your body will store less fat, and you’ll
maintain a more stable blood-sugar level because you won’t need as
much sugar for energy.
When you don’t produce the required amount of energy from fat,
your body instead relies too heavily on sugar, usually producing
fatigue. This common symptom, fatigue, is one of the most common
complaints heard by doctors. It comes in physical and mental forms,
or in a combination of both. Some people say they just can’t perform
as they did when they were younger. But age is no excuse for a lack
of energy. Physical fatigue may strike at a particular time of the day,
or it may make you feel exhausted from the time you awaken. You
may feel you don’t have the energy to do extra chores, go out at night
or even get up in the morning. Mental fatigue is also common, mak￾ing it difficult to think clearly or make decisions. This can affect anyone

from students and executives to children and adults at all ages.
To avoid fatigue and instead access unlimited energy from your
fat-burning system, two things must occur. First, you need to develop
and utilize the body’s aerobic system. Second, you need to provide
that system with the proper fuel in the form of food. These items are
discussed in the coming chapters.
To maintain efficient fat-burning, you also must burn some sugar.
Herein lies another example of balance. Both fat and sugar are almost
always being burned for energy at all times. It’s a question of how
much of each we use. Right now, you may be getting half of your
energy from fat and half from sugar. When you improve your aerobic
system and fat-burning capabilities, you may be able to obtain 70 per￾cent of your energy from fat and 30 percent from sugar. But many
people only get 10 percent of their energy from fat, forcing a full 90
percent to come from sugar. That’s a very inefficient and unhealthy
way to get energy. This is the typical situation in people who are
fatigued and attempt to obtain more energy from sugar because they
can’t get much from fat. And when fat is not used for energy, it is
stored in the body. This book explains how to reverse this situation
and improve your fat-burning system.
This mix of fuels used for energy can be easily measured in a per￾son, and is something I have done during my years in practice and
during other research. So when I say you can improve your fat-burn￾ing capability, it is because I have seen and recorded these changes in
actual patients. These measurements are taken using a gas analyzer,
which measures the amount of oxygen a person inhales and the
amount of carbon dioxide exhaled. The ratio of carbon dioxide to oxy￾gen gives the percentage of fat and sugar that is used for energy. This
is referred to as the respiratory quotient, or RQ. I usually don’t recom￾mend getting tested because for most people, when fat-burning is
poor, there are plenty of signs and symptoms. These include the obvi￾ous — increased fat storage. Others include fatigue, blood sugar prob￾lems, hormone imbalance, poor circulation and even common physi￾cal injuries. Others are discussed throughout this book. In general, as
fat-burning improves the body is able to correct many of its own
problems. The bottom line — more fat-burning improves health, fit￾ness and human performance.