|
- The insulin surge and potential hypoglycemia that is
theorised to occur if sugary drinks are taken in the minutes
before a competitive event is a potential in sedentary individuals
eating sweets, but rebound hypoglycemia does not appear
to be a practical problem for athletes. However, choosing
to err on the side of caution, most authorities recommend avoiding
all simple carbohydrates for the several hours before an event,
starting carbohydrate supplementation in the few minutes immediately
preceding the start of the activity.
- Even though it appears that simple carbohydrates should be avoided
in the hour or two immediately preceeding your ride, there is
almost unanimous support for the benefits of a pre ride meal
of complex carbohydrates 3 or 4 hours before the event. These
carbohydrates not only "top off" your muscle and liver
glycogen stores, the slow digestion and absorption of the complex
carbohydrates may provide an ongoing glucose supplement from
your intestinal tract even after the ride has started. And recent
studies have demonstrated that using commercial energy bars
or a high fat meal offer no performance advantages over a more
traditional and less expensive complex carbohydrate such as
oatmeal.
- Maximizing liquid carbohydrate replacement
while riding is a very important strategy for events lasting
more than 2 hours. 1 to 2 grams of carbohydrate per minute can
be absorbed and utilized to sustain prolonged exercise. In extreme
events such as the Tour de France, as much as 50% of the daily
energy expenditures can be replaced while on the bike. Although
the sugar concentration has an effect on the rate of stomach
emptying, the volume of fluid in the stomach plays a role as
well. Keeping the stomach filled by frequent drinks will enhance
the rate of gastric emptying.
As
sugar concentration increases, the risk of nausea and bloating
rises as well. Almost everyone can tolerate a 7 to 10% concentration
of glucose, but many cyclists will tolerate solutions of up to
15% to 20%. And the use of polymers will allow more carbohydrates
to be ingested and absorbed while limiting to some degree the
overall concentration of the solution. Fluid replacement rates
of 500 ml per hour are appropriate for the majority of cyclists
during prolonged exercise, but rates of up to 1 to 2 liters per
hour have been reported in the Tour de France. The risk here is
hyponatremia with the larger volumes.
As
an example, starting an event with 400 ml of an 18% glucose polymer
solution in the stomach and drinking 100 ml every 10 minutes will
deliver 108 grams of carbohydrate with 600 cc of fluid every hour.
- Take advantage of the "glycogen window" that is open
in the 4 hours immediately following vigorous exercise. During
this interval, ingested carbohydrate will be converted into
muscle glycogen at about 3 times the normal rate (and "the
earlier the better" as some data suggests a 50% fall
in the conversion rate by 2 hours and a complete return to
normal repletion rate by 4 hours). Muscle glycogen repletion
(after a 2 plus hour ride) usually proceeds at a rate of 5%
per hour, and although it may require up to 48 hours for complete
muscle glycogen replacement, most is accomplished during the
first 24 hours post event. The athlete who is training daily,
or is in a multi-day event, can use this glycogen window to
their advantage to get a jump on the normal repletion process
and minimize the chance of chronic glycogen depletion (and
the fatigue that goes along with it). There is also suggestive
evidence that the muscle stiffness that occurs after vigorous
exercise is related to muscle glycogen depletion, so rapid
repletion may have an added benefit of minimizing this day
after effect. One caution though - many simple carbohydrate
snacks such as chocolate chip cookies are more than 30% fat
and if eaten in large quantities might exceed your planned
daily fat intake of 20-30% of Calories. In contrast, complex
carbohydrate foods such as pasta, bread, and rice offer significantly
more carbohydrate per gram or ounce. And there are even special
"recovery drinks" available.
- Vegetarian diet. A growing
number of cyclists are moving toward meatless meals or a completely
meat free nutritional program. Not only are vegetarians
healthier, with lower rates of chronic diseases such as heart
disease, obesity, and colon cancer, but the fact that their
diets are high in carbohydrates means they are constantly
"carbo loaded".
There
are a few tips to remember if you are considering a life style
change.
-
Vegans,
who eat no animal products whatsoever including dairy, need
to be certain they get enough
-
vitamin
B12 (from supplements and fortified foods such as cereal,
bread, pasta, and brewer's yeast)
-
iron
(from beans, kale, dried fruit, and collard greens). Don't
use supplements unless recommended by your physician because
of the potential toxicity of too much iron.
-
calcium
(dark leafy vegetables, brocoli, citrus fruits)
-
Eat
"balanced" protein (because of the mix of amino
acids, non meat protein foods need to be eaten in combinations
- same meal or in consecutive meals - to have the right balance
of amino acid building blocks to allow the body to use them
to build and repair tissue).
-
pinto
beans and rice
-
grains
(rice, bread, cereal) and legumes (peas or beans)
-
Eat
a bit more than if you were eating meat as a protein source.
For example a 3 ounce piece of meat contains about 21
grams of protein and can be substituted with a cup of
cooked grain and a cup of cooked bean
|
