Why Is The Glycemic Index Important?

The GI’s importance relates to blood sugar’s e ects on the hormone insulin,
the primary hormonal mediator of fat storage. Among its hundreds of dif-
ferent functions, the body uses the hormone insulin to control the amount
of sugar (glucose) in the blood, help pull amino acids into the cells, turn on
protein synthesis in lean tissues and regulate body fat storage.

Problems with the body’s ability to regulate blood glucose appear if insulin
does not properly bind to its receptors on the membranes of the cells or if
the cells do not readily accept blood sugar.

As already indicated, the general name for the failure of normal amounts
of insulin to maintain blood sugar (i.e., glucose) within acceptable levels
is insulin resistance. When insulin does not bring blood sugar down after
meals, the body secretes higher amounts of insulin until serum glucose
levels eventually fall.

Not surprisingly, diets and nutrients, which reduce the amount of insulin
required by the body, also appear to reduce the tendency toward excessive
weight gain, especially in insulin insensitive people.

Controlling the GI of meals allows a person to keep a steady and predict-
able blood sugar level, which can lead to possible improvements in body
fat levels, energy levels, etc. For the diabetic (the original reason the GI was
invented), it can mean the di erence between life and death.

Since the hormone insulin is well known for its ability to store glucose in
muscle, increase protein synthesis and possibly increase muscle mass, it
has predictably gotten the attention of bodybuilders and other athletes.
In fact, it is sometimes said that insulin is a primary anabolic hormone pro-
duced by the body.

Some researchers feel that insulin is almost as important to lean muscle
tissue as the anabolic hormones testosterone and growth hormone ( GH).
Insulin has direct e ects on IGF-1 binding proteins (IGFBPs) and directly
mediates some of the e ects of IGF-1.

Unfortunately, insulin certainly has its downside. Of course, most people
know that insulin metabolism out of control will make a person rather fat,
since insulin is a primary hormonal mediator of fat storage.

Insulin resistance increases the number of calories stored as fat and in-
creases the amount of fat produced by the liver from carbohydrates. It
gets worse: it turns out that insulin plays a big role in whether we produce
our own fat from carbohydrates. And if we are making even a little fat, we
turn o our ability to burn fat because the body does not make new fat and
burn already stored fat at the same time.

Of course, the concept of “ insulin management” for adding new muscle
to the hard-training athlete’s frame is all the rage with various bodybuild-
ing magazines, supplement companies and nutritional guru types. If you
can manage insulin via the GI correctly, you can add new muscle without
adding a great deal of body fat. This is the goal of proper insulin manage-
ment.

It’s obvious that athletes and bodybuilders are far more aware than the
general public of the importance of insulin, hence the popularity of insulin
potentiating compounds such as chromium and vanadyl sulfate.

Some bodybuilders have chosen to go the Kamikaze route by injecting in-
sulin directly, but it does not take a rocket scientist to realize how danger-
ous this practice is.

Can you say “coma?”

Also, many bodybuilders who play with insulin injections end up looking
more like the Michelin Man than a bodybuilder.

One thing should be clear by now: proper insulin management is of para-
mount importance whether for athletes looking to add new muscle with-
out adding body fat, as well as for non-athletes trying to avoid a host of
medical ills.

Athletes want to improve their insulin/blood sugar metabolism because
they know it can lead to increases in lean mass, glycogen storage in mus-
cle, and decreases in body fat. The avoidance of future medical problems
is certainly not a bad motivator, either
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Carbohydrates

Carbohydrates, or sugars, are made primarily of carbon, hydrogen and oxy- gen atoms that cyclize into a ring. Carbohydrates can be “simple” or “complex” depending on the number of rings you hook together and the way in which they hook together. Though the rings can be slightly di erent, their common theme is the ring struc- ture as their nal shape. Similar to amino acids and fats, when you link the simple units (the sug- ars) together you get carbohydrates with di erent properties. You can link glucose units together to get a glucose polymer. In fact, when the body stores units of glucose linked together in the liver and muscle, it is called “ glycogen,” a term with which most people are familiar.

You can also link di erent kinds of sugars to get di erent products. For in-
stance, if you combine glucose with fructose you get sucrose (table sugar).
If you combine glucose with galactose you get lactose (milk sugar), and so
on.

Link a bunch of sugars together and you get polysaccharides. Combine
two sugars together like the previously mentioned lactose and you get a
disaccharide. Of course, by themselves they are called monosaccharides.
Are you starting to see a repeating theme here?

Link a simple unit together with other units and you get a product the body
can do all sorts of things with. Linking units together gives you a product
(fats, carbs, and proteins), and breaking down the products into units (ulti-
mately) gives you energy.

You will notice I have not mentioned the “essential carbohydrates” because
there is no such thing! Though the body runs best on an intake of some
carbs in the diet, the body can make its own carbohydrates from protein
and other non-carbohydrate substrates, as mentioned in the protein sec-
tion.

Digestion reverses the process: the body breaks down complex carbohy-
drates into simple carbohydrates and ultimately blood sugar (glucose)
which can then be used for many di erent functions, such as the produc-
tion of ATP (the body’s universal energy molecule). Depending on the car-
bohydrate and other factors, di erent carbohydrates will have di erent ef-
fects on blood sugar; in particular, how fast blood sugar rises and falls.

The ability of a carbohydrate food to raise blood sugar quickly or slowly is
called the glycemic index ( GI). The GI was developed to track how di erent
foods a ect blood sugar.

Interestingly, many carbohydrates that are considered“complex” have been
found to raise blood sugar rapidly while a few “simple” carbohydrates don’t
have a dramatic e ect on blood sugar. The GI rating of a food is based on
how much blood glucose rises after consuming a carbohydrate food over a
2 hour period. This is compared to a reference, glucose, a simple sugar.

Some GI scales now use white bread as the reference, but we will use the
glucose scale in this chapter. For instance, if you consume 50 grams of
glucose (yuk), you will get dramatic elevation in blood sugar. If you eat, say
50 grams of carbs found in the form of oranges, your blood glucose would
probably rise approximately 44 percent when compared to glucose. So,
the GI rating for oranges would be 44 on the glucose scale. Using white
bread as the reference carbohydrate, it would be a di erent number. Capi-
che?
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