Understanding the Importance
of Insulin

    I'm going to talk to you about the hormone whose name you've heard many times: insulin. Some
of the content of this chapter is fairly complex, but I think you ought to read it carefully. Because
for many of you, the answers to your battle with the bulge and concerns about long-term health
issues are here.
    Almost everyone knows that insulin is given to people with a certain kind of diabetes, to help
control their blood sugar levels when their own supplies become depleted or insufficient. Insulin
is one of the most powerful and efficient substances that the body uses to control the use,
distribution and storage of energy. At its most basic, insulin is the control hormone for glucose, a
basic form of sugar. So listen up.
    Your body is an energy machine, never resting, always metabolically active-and it powers its
operations mainly through the use of glucose in the blood, which is why glucose is
interchangeably called blood sugar. The body must maintain a certain level of glucose in the
blood at all times. So when there is no carbohydrate food source to make glucose, the liver will
actually convert protein to glucose. Remarkably, even on a prolonged, total fast, a healthy body
can maintain its glucose level within a rather narrow normal range. As a general rule, of course,
the body obtains its principal supply of fuel from food.

What Happens to a Meal

    You sit down at the table and consume a three-course dinner. Somewhere between chewing
and excreting, your body absorbs certain substances from your food, mostly across the surface of
your small intestine. From the carbohydrate you eat, your body will absorb sugars, all of which
are, or quickly and easily become, glucose. From fat, it absorbs glycerol and fatty acids, and
from protein, it absorbs amino acids, the building blocks of all cells.
    Obviously, if you eat a lot of carbohydrate, you'll end up with a lot of glucose in your blood.
Sounds good, doesn't it? All that energy coursing through your system. Eat sugar, starches and
fruits and you're going to get those blood-sugar levels up fast, aren't you? If you love candy bars,
perhaps you're saying, "That's great-the more I eat, the more energy I'll have."
    Alas, a bad mistake. You see, the human body evolved and primitive humans thrived as
hunter-gatherers who subsisted primarily on meat, fish, vegetables, fruit, whole grains and seeds
and nuts. Candy bars were few and far between. The human body is used to dealing with
unrefined foods as they occur in Nature. Consequently, your body's capacity to deal with an
excess of processed foods is pretty poor, which is why our twenty-first-century way of eating so
often gets us into trouble.
    If you don't understand this yet, let's look at what insulin and the other energy-controlling
hormones do when you eat.