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- 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.
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Vegans, who eat no animal products whatsoever including dairy, need to be certain they get enough
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vitamin B12 (from supplements and fortified foods such as cereal, bread, pasta, and brewer's yeast)
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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.
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calcium (dark leafy vegetables, brocoli, citrus fruits)
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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).
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pinto beans and rice
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grains (rice, bread, cereal) and legumes (peas or beans)
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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
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