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 any-
16 • IN FITNESS AND IN HEALTH