by Robh » Sun Feb 24, 2008 10:31 pm
The following text below is from Hammer Nutrtion, most of my rides are very early in the morning like 4:30am during the week so I don't have time for breakfast :-
OK, you're convinced that it's a good idea to eat at least three hours prior to the start of your race. “But wait,†you say. “My race starts at 7 a.m. Are you telling me I have to get up at 3 a.m. or so just to eat?†Well, you could get up to eat if you're so inclined, but you don't have to. The fuel you've got stored in the muscles? It's going to be there, full strength, even after a night-long fast (really). In the morning your brain may be saying, “I'm hungry,†but your muscles are saying, “Hey, we're good to go.â€
Bottom line: do not sacrifice sleep just to eat. If you've got an early morning race start, the best strategy is:
Eat a high quality meal the night before (topping off liver glycogen stores)
Get an adequate amount of sleep
Have 100-200 calories of easily digested fuel (Hammer Gel is ideal) 5-10 minutes prior to the start of the race
That's right, 5-10 minutes prior, not one or two hours prior. The key, in terms of muscle glycogen depletion rates, is in the timing. If you must eat before the start of your race, you need to complete consumption three hours prior. If that's not logistically feasible, have a little something 5-10 minutes prior. Do that and you won't expend your hard-earned glycogen too rapidly.
If you consume high glycemic carbohydrates such as simple sugars (or even the preferred complex carbohydrates such as starches and maltodextrins) within three hours of exercise, you can expect the following, with possible negative effects on performance:
Rapidly elevated blood sugar causes excess insulin release, leading to hypoglycemia, an abnormally low level of glucose in the blood.
High insulin levels inhibit lipid mobilization during aerobic exercise, which means reduced fats-to-fuels conversion. Our ability to utilize stored fatty acids as energy largely determines our performance, which is why we can continue to exercise when our caloric intake falls far below our energy expenditure. We want to enhance, not impede, our stored fat utilization pathways.
A high insulin level will induce blood sugar into muscle cells, which increases the rate of carbohydrate metabolism, hence rapid carbohydrate fuel depletion. In simple terms: high insulin means faster muscle glycogen depletion.
You must complete your pre-race fueling three or more hours prior to the start to allow adequate time for insulin and blood glucose to normalize. After three hours, hormonal balance is restored, and you won’t be at risk for increased glycogen depletion. Eating within three hours of a race promotes faster release/depletion of both liver and muscle glycogen and inhibits fat utilization. The combination of accelerated glycogen depletion and disruption of your primary long-distance fuel availability can devastate your performance.
But I’m hungry!
Recall that I mentioned earlier that muscle glycogen, the main fuel recruited for the first 60-90 minutes of exercise, remains unaffected by a nightlong fast. When you awaken in the morning, you haven’t lost your primary fuel supply, and can’t add to it by eating within an hour or two of exercise. That’s absolutely correct, and believe it or not, being hungry before an event won't inhibit performance.
However, hard-training athletes often do wake up very hungry and feel they need to eat something before their workout or race. This is especially true for half and full iron-distance triathletes, who start very early in the morning in the water, swimming for up to an hour or more where consuming food is not possible.
What to do? Try either of the following suggestions to help with this problem:
Just start anyway, realizing that hunger is not a performance inhibitor, and begin fueling shortly after you start, when you get into a comfortable rhythm. The hunger sensation will diminish almost as soon as you begin to exercise, and you’ll actually be benefiting, not hurting, your performance by following this procedure. You can safely use Sustained Energy, Perpetuem, HEED or Hammer Gel, or any combination thereof, as soon as you want after exercise commences. For details regarding appropriate amounts, please refer to the article “Proper Caloric Intake During Endurance Exercise.â€
If you feel that you absolutely must eat, consume 100-200 calories about five minutes before start time. By the time these calories are digested and blood sugar levels are elevated, you’ll be well into your race, and glycogen depletion will not be negatively affected. In this regard, good choices are one or two servings of Hammer Gel or a generous drink from a premixed bottle of Sustained Energy or Perpetuem. This strategy is especially appropriate for triathletes who will hit the water first and not have a chance to eat right away. Small amounts of nutrient-dense fuels, such as those named above, go a long way to stanching hunger pangs.
Sleep or eat?
Should you get up during the wee morning hours just to get in a meal three hours before your race or workout? My answer is NO—rest will help you more. Much restorative physiology occurs during sleep, so don’t sacrifice sleep just to eat. If you’re a fit athlete, one who has been replenishing carbohydrates immediately after each exercise session, you have approximately 60-90 minutes of muscle glycogen, your premium fuel, available. As long as you begin fueling shortly after the race begins, perhaps 10-20 minutes after the start, your performance will not be affected negatively. If you start fueling shortly after your race begins, it’s actually OK to start your race a little on the hungry side. Topping off liver glycogen stores is always a good idea, but not at the expense of sacrificing sleep, and certainly not at the expense of depleting muscle glycogen stores too quickly (by eating too soon before exercise).
Are there any exceptions to the three-hour rule?
When you’re competing in races in the 90-minute range or shorter (personally, I prefer an hour limit), fasting three hours prior to the start of the race is not necessary. Consuming some easily digested calories an hour or two prior to the start will not negatively affect performance, and may actually enhance it. Here’s why:
As we’ve discussed earlier, when you consume calories sooner than three hours prior to the start of a race, you accelerate the rate at which your body burns its finite amounts of muscle glycogen stores. In events lasting longer than 60-90 minutes, refraining from calorie consumption for the three-hour period prior to the start is crucial because you want to preserve your glycogen stores, not accelerate their depletion. Muscle glycogen is the first fuel that the body will use when exercise commences, and your body only has a limited supply of this premium fuel. If your workout or race goes beyond the 60-90 minute mark, you don't want to do anything that will accelerate muscle glycogen utilization. However, when you consume calories within three hours of a race, that's exactly what will happen; you'll increase the rate at which your glycogen is burned.
During shorter distance races, however, accelerated rates of glycogen depletion/utilization are not problematic. You don’t need the calories for energy, but the presence of carbohydrates will elevate glycogen utilization. In a short race, that’s what you want.
Dr. Misner explains that prior to shorter-duration races, “… consuming a few easily digested carbohydrates [such as a serving or two of HEED or Hammer Gel] will advance performance, because carbohydrates consumed prior to exercise make the body super-expend its glycogen stores like a flood gate wide open." In other words, if you eat something 1-2 hours prior to the start of a short-duration race, thus causing the insulin "flood gates" to open, yes, you will be depleting your glycogen stores at maximum rates. However, at this distance it’s a beneficial effect, as glycogen depletion is not an issue when the race is over within at most 90 minutes.
This advice assumes that you have been effectively refueling your body after each workout, as this is the primary way to increase muscle glycogen (see the article “Recovery—A Crucial Component of Athletic Success†for details).
Bottom line: Fast three hours prior to the start of a longer-duration event (60-90+ minutes). For shorter events, consuming a small amount of fuel an hour to two prior to the start may enhance performance.
Summary & pre-race meal suggestions
You work so hard throughout your training, making sure you tune your diet, supplement program, training, and recovery to exactly fit your personal needs. Following these steps regarding your pre-race meal will put the final touches on all of your hard work, giving you the best advantage for your important race.
Eat a pre-race meal of 200-400 calories at least three hours before exercise.
Focus on complex carbs, starches, and a little protein for your pre-race meal.
Avoid high fiber, simple sugars, and high fat in your pre-race meal.
If you must, consume a small amount of your supplemental fuel (Hammer Gel, etc.) about five minutes before exercise.
Make sure that you re-supply your muscle glycogen by eating a good recovery meal after your workouts.
Any of these pre-race meal suggestions will keep you in the preferred 200-400 calorie range