Download Carb Loading

Sports Nutrition
Lesson 20
Carb Loading
CHO is an important fuel for exercise. Because
the amount of CHO stored in the body is
limited, muscle and liver glycogen depletion
could be a factor that limits performance in
certain types of exercise.
Carb Loading
Carbohydrate loading, also known as
glycogen loading and glycogen
supercompensation, is technique designed to
promote a significant increase in the glycogen
content in both the liver and muscles in an
attempt to delay fatigue.
Carb Loading
Carb loading is primarily suited for those
competing in
- long-distance running
- swimmers
- bicyclists
- triathletes
- cross-country skiers
Carb Loading
Also those who are involved in prolonged stop
and go sports such as
soccer
lacrosse
tournament play sports such as tennis and
hand-ball
Carb Loading
Sports scientists generally agree that CHO
intake during loading should be about 810gm/kg of body weight.
It is important to individualize as carbs in
excess of use can be converted into body fat.
Carb Loading
If for some reason, the 8 day protocol cannot
be followed, a rapid one may be effective.
One day of a high CHO intake, about 10gm of
high glycemic-index CHO/kg of body weight
nearly doubled the muscle glycogen
concentrations.
Carb Loading
Just before the 1 day CHO feeding was a 3
minute maximal-intensity exercise. Muscle
glycogen levels were comparable to the 8 day
protocol.
Carb Loading
Glycogen content in the muscle has been
reported to increase
2-3x normal, and last
3 days in a rested
athlete. It is important
to taper and rest 2 days
prior to an event.
Carb Loading
How can I tell if the carb loading has been
effective?
Muscle biopsy is the most accurate, but hardly
practical.
The practical way is to monitor your body
weight.
Carb Loading
Glycogen is stored in the body in hydrated
form. Weight gain may
occur with CHO loading.
Weigh yourself each
morning after you go to
the bathroom.
Carb Loading
About 3gm of water are bound to each gram of
stored glycogen.
So if your body stores 300-400gm of glycogen,
your body weight will increase about 1,2001,600 gms or 2.5-3.5 pounds above your
normal weight during the loading phase.
Carb Loading
Remember, studies show that CHO loading
makes no difference in shorter term exercise.
The athletes that benefit are the long
endurance competitors.
Carb Loading
From a performance standpoint, the extra body
weight may be a disadvantage. In activities
where moving the body weight is important,
extra energy will be required to carry the extra
body weight.
In hot environments this could be an advantage
as the extra water will be available for sweat.
Carb Loading
Problems with Carb Loading
There is a potential hazard if you are diabetic
Carb loading has been known to significantly
increase cholesterol levels.
Some have shown electrocardiographic
abnormalities when the classis carb loading
protocol is used.
Carb Loading
Other problems associated with this diet
change are:
- diarrhea
- nausea
- cramping
Carb Loading
Key Points
- Carb loading is not a technique for all types
of athletes.
- Carb Loading may benefit marathoners.
- Carb loading methods increase muscle
glycogen stores, but tapering exercise and
rest are essential points.