|
|
 |
By T'ai
Erasmus, ISSA
|
|
If you are athletic you should know about the glycemic
index.
Dr. David Jenkins developed the glycemic index to assist diabetics in
their fight to stabilize insulin levels. To date, the GI is employed
as a powerful tool in the treatment of diabetes, hypoglycemia, obesity,
catabolism and fatigue, just to name a few. The GI is such an effective
tool, I believe every athlete should refer to the GI when making smart
food choices.
|
| The
GLYCEMIC INDEX and CARBOHYDRATES . . . |
|
More specifically, the glycemic index was designed to indicate
the rate at which carbohydrates enter the bloodstream, and
their effect on insulin. As simple sugars enter your blood
stream, insulin is released. This reaction drives sugar into
your cells. Eventually, this leads to energy impairment,
insulin resistance, and potentially later in life adult onset
diabetes. In effect, insulin is the catalyst responsible
for removing sugar from your blood.
Low-glycemic foods are absorbed slowly so they do not cause
an insulin spike. The term "insulin spike" refers
to a sharp rise in resting insulin, followed by a valley
of low circulating insulin. High-glycemic foods on the otherhand
cause a large influx of insulin to lower blood sugar. Therefore
when you experience a drop in blood sugar, energy level,
mood, and performance are compromised.
|
| The
ATHLETE's Secret! |
| So, how do you prevent this from happening? Because carbohydrates
control the amount of sugar in your blood, athletes should
eat low-glycemic carbs throughout the day to provide an even
flow of blood sugar. In effect, eating consciously will provide
your performance machine with a reliable low flow of insulin.
This is essential for energy production, fat regulation and
anabolic drive. |
| Eat
Your Vegetables!! |
| The next question is how do I choose the right fuel for my
body? To start, carbohydrates are divided into two classes,
simple and/or complex depending on their chemical structure.
I prefer to classify carbs as starchy or fibrous. I find this
way of thinking simple, and easy for clients to follow. For
example potatoes, rice, pasta and bread would be considered
starches. Broccoli, green beans, asparagus and brussel sprouts
are all referred to as fibrous. When mother told you to eat
your vegetables, she was right! |
| To
your advantage there are factors, which influence GI.
Some of these factors are as follows: |
- Type of sugar - As you will observe in the partial
list below, glucose has a higher GI than fructose. Northern
Hemisphere fruits tend to have a lower GI. This is because
of their higher fructose content. Equatorial fruits,
with the exception of peaches and nectarines have a higher
GI. Living in Canada has its perks, if you are a fruit
fanatic!
- Nature of starch - The amylose:
amylopectin ratio of starches can effect
the GI of foods. Amylopectin is digested
faster than amylose. Legumes for example
have a higher amylose: amylopectin ratio.
Thus providing a lower GI. White rice
on the otherhand contains more amylopectin.
Consequently the GI is higher.
- Particle
size -
Liquid
versus
solid
food.
Juicing
vegetables
is
a perfect
example
of
how
we
remove
valuable
fiber
from
an
already
naturally
perfect
food.
- Cooking
methods -
High
temperature
cooking
effects
the
gelatinisation
of
fruits
and
thus
increasing
GI.
Stewed
fruits
have
a
higher
GI
than
fresh
fruits.
- Fat -
Ice
cream
for
example
has
a
low
GI
because
of
its
fat
content.
This
could be
potentially
misleading
because
of
the
undesirable
effects
of
both
sugar
and
certain
types
of fat.
But,
there
is
a
way
to
use
fat
to
your
advantage.
Stop
consuming
saturated fats.
Your
body
already
manufactures
saturated
and
monounsaturated
fats
from
carbohydrates.
Hence,
they
are
not considered
essential.
Use
essential
fats
instead.
More
specifically
Omega-3
and
Omega-6
fats.
These
fats
have the
ability
to
lower
the
GI
of
foods,
enhance
fat-loss,
increase
energy
levels,
improve
hormone levels
and
have
many
other
health
benefits.
- Fiber -
There
are
different
types
of
fiber.
Insoluble
fibers
appear
to
have
no
immediate
effect.
However, soluble
fiber
can
decrease
the
absorption
rate
of
sugar,
hence
lower
GI.
Again,
eat
your veggies!
|
| If
athletes are serious about results . . . . |
| If athletes are serious about results, the glycemic index
should be the foundation of every sports nutrition program
they follow. I have worked with athletes from almost every
sport. It still astonishes me how unconscious most athletes
are about what they put in their bodies. A question I ask to
every athlete is what kind of records would you break if you
fueled your body right? Think about it!
To better understand some of the differences between carbohydrates,
below is a partial list of food items and their glycemic
values. The right hand column represents those foods best
suited for improving athletic performance.
|
A PARTIAL LIST OF THE GLYCEMIC INDEX
(Source:
Jenkins et al., American Journal Of Clinical Nutrition,
1981)
| |
|
|
|
|
|
|
|
| CONSUME
LESS |
|
|
CONSUME
MORE |
| |
|
|
|
|
|
|
|
| Food |
|
Glycemic
Index |
|
|
Food |
|
Glycemic
Index |
| |
|
|
|
|
|
|
|
|
Sugars
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
| Glucose |
|
100 |
|
|
Fructose |
|
32 |
| Honey |
|
87 |
|
|
|
|
|
| Sucrose |
|
59 |
|
|
|
|
|
| Lactose |
|
65 |
|
|
|
|
|
| Maltose |
|
150 |
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
Vegetables
& Legumes
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
Parsnips
|
|
98 |
|
|
Soybeans |
|
15 |
| Carrots |
|
92 |
|
|
Kidney
Beans |
|
42 |
| White
Potatoes |
|
70 |
|
|
Lentils |
|
41 |
| Mashed
Potatoes |
|
80 |
|
|
Sweet
Potatoes |
|
48 |
| Broad
Beans |
|
75 |
|
|
Yams |
|
51 |
| Corn |
|
78 |
|
|
Black-eyed
Peas |
|
33 |
| Baked
Bean |
|
69 |
|
|
Chickpeas |
|
47 |
| |
|
|
|
|
Lima
Beans |
|
46 |
| |
|
|
|
|
Pinto
Beans |
|
55 |
| |
|
|
|
|
Split
Peas |
|
45 |
| |
|
|
|
|
|
|
|
|
Fruits
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
| Oranges |
|
62 |
|
|
Northern
Fruits |
|
30-40 |
| Bananas |
|
76 |
|
|
Apples |
|
52 |
| Raisins |
|
68 |
|
|
Peaches |
|
29 |
| Grapes |
|
62 |
|
|
Grapefruit |
|
36 |
| Pineapple |
|
94 |
|
|
Pear |
|
47 |
| Watermelon |
|
103 |
|
|
Plum |
|
34 |
| Equatorial
Fruits |
|
60-70 |
|
|
Cherries |
|
32 |
| Dried
Fruits |
|
65-75 |
|
|
|
|
|
| |
|
|
|
|
|
|
|
|
Grains & Pasta
|
|
|
|
|
|
|
|
| |
|
|
|
|
|
|
|
| White
Flour Spaghetti |
|
56 |
|
|
Whole
Wheat Spaghetti |
|
40 |
| Corn
Flakes |
|
85 |
|
|
Oats |
|
48 |
| White
Rice |
|
81 |
|
|
Brown
Rice |
|
79 |
| White
Flour Pancakes |
|
66 |
|
|
Buckwheat
Pancakes |
|
45 |
| White
Bread |
|
76 |
|
|
Whole
Wheat Bread |
|
64 |
| Instant
Rice |
|
128 |
|
|
Barley |
|
36 |
| Linguine |
|
65 |
|
|
Rye |
|
48 |
| |
|
|
|
|
Wheat |
|
59 |
| |
|
|
|
|
|
|
|
|
| References
Cited: |
|
1. Jenkins DJA. Lente carbohydrate: a
newer approach to the management of diabetes. Diabetes
Care 1982; 5:634-639.
2. Brand Miller, J., Forster-Powell, K. and Colaguri, S.,1996, The
GI Factor, Hodder & Stoughton, Sydney.
3. Hatfield, F. C., and Gastelu, D., 1997, Performance Nutrition,
International Sports Sciences Association, Santa Barbara
4. Wolever, Thomas M.S., 1999, The Glucose Revolution, Marlowe & Company,
New York
|
T'ai Erasmus is a certified
personal fitness trainer, and sports nutritional consultant
working in Vancouver. To book sessions or a consultation
he can be reached by calling 604-329-7867or by e-mail at
tai@taierasmus.com.
|
|
|
