Question:
From Cedar Rapids, Iowa, USA:
My cousin, an R.N., says she has heard that diabetic marathon runners often
"charge" themselves with extra carbohydrates for a few days prior to
running. If so, what does it entail, and would it help her two daughters
(ages 13 & 16) who are Type 1 (both diagnosed at age 3)?
They are avid
volleyball players for their school and metro teams. When they play in
very intensive 2-day tournaments, they cut back their Humalog 2-units
starting the morning just before the tourney (assuming a blood glucose of
150 or less) and stay at that dose until they finish their last game, the
next afternoon or evening. They leave their Ultralente at night the same.
Also, they eat/drink fruit and juices, pudding, etc. in addition to their
regular meals, yet they still "run out of steam" during the second day's
games. Any thoughts would be appreciated.
Answer:
Research has shown that a particular combination of diet and exercise results
in a significant "packing" of muscle glycogen. The term carbohydrate loading
or supercompensation is used for this procedure among endurance athletes. The
classic procedure for achieving the supercompensation effect is to reduce the
muscle's glycogen content with prolonged steady rate exercise 6 days before
competition. Because supercompensation occurs only in the specific muscles
exercised, the athlete should be sure to engage the muscles involved in
his/her sport. (For a marathon runner, a 15 to 20 mile run is usually
necessary, whereas for bicycling, moderately intense submaximal exercise for
90 minutes is required.) Then the athlete maintains a low-carbohydrate diet
for several days to further deplete glycogen stores. During this time
moderate training is continued. Then, at least two days before the
competition, the athlete switches to a high-carbohydrate diet and maintains
it up to and including his/her pre-game meal. The 2 to 3 day requirement for
a high carbohydrate diet is important because it generally takes this long
for full restoration of muscle glycogen following severe depletion.
Athletes with diabetes should not practice carbohydrate loading, especially if
it requires a period of time where carbohydrate restriction in included.
Adjustment of insulin dosages to this practice is just too difficult.
However, on pre-competition day, I would suggest that the girls eat more
foods that are high in carbohydrate and decrease their training to increase
glycogen stores. Because regular exercise requires frequent replenishing of
stored carbohydrate, more carbohydrate may be needed in their diet. Remember that the girls' insulin dosages may need to be increased slightly during
this period.
Depleted glycogen stores can cause fatigue and poor performance. This may be
why the girls are running out of steam on the second day of their tournament.
Here are some suggestions for food intake that might be helpful to your
cousin and her girls:
- The night before their competition, the girls should try to eat a
high carbohydrate meal to increase glycogen stores. Examples of carbohydrate meal to increase glycogen stores. Examples of foods that are
high in carbohydrates are spaghetti, rice, potatoes, squash, noodles, bread,
muffins, yogurt, rolls, etc. Avoid foods that contain large amounts of fat in
addition to carbohydrate, such as pizza and ice cream.
- On the day of competition, the girls should try to eat a light
breakfast. Toast, juice or fruit, and cereal with skim milk are good
choices. For lunch, a turkey sandwich with skim milk and fruit.
- A light pre-game meal should be eaten 1 to 2 hours before the
event. (Carbohydrate and protein but a minimal amount of fat.) If too much
protein is ingested and too little carbohydrate, the girls will deprive their
muscles the energy they need to perform well.
Another reason the girls may run out of steam is that they may not be
adding enough carbohydrate during their activity period. Fruit juice can be a
good source of carbohydrate and fluid
but should be diluted with water (1 part water [1 cup] to 1 part juice [1 cup
juice]). They may want to consume 10 to 15 grams of carbohydrate every hour
during a long event.
A reference that may be of some additional help is Nutrition and
Sports Performance: A Guide for Physically-Active Young People, a pamphlet
put out by the American College of Sports Medicine, P.O.
Box 1440, Indianapolis, IN 46206-1440.
PL
Original posting 18 Apr 97