SUMMARY OF FUEL ADDITIVES AND THEIR EFFECT ON PERFORMANCE
Sherman, W. M., & Lamb, D. R. (Eds.). (1995). Proceedings of the Conference on Nutritional Ergogenic Aids. Sports Nutrition, 5, Supplement.
Evidence now supports carbohydrate (CHO) loading with a pre-event meal of 60-70% CHO content. This is potentially beneficial for events requiring very extended endurance activities (e.g., marathon running, an all-day swim meet, a soccer game, very demanding practice sessions). It was recommended that CHO drinks should be consumed during the event and/or training and up to 40-60 gm of CHO taken hourly for five hours after the activity.
The recently promoted "fad" of increasing dietary fat so that during an activity the body will use it as fuel and save ("spare") CHO for later is unsupported by facts. It could even be dangerous.
Branch Chain Amino Acids
These are promoted as a means to stimulate an increase in the brain's level of serotonin, a central nervous system neurotransmitter that could reduce fatigue sensations recognized by the brain. At this time there is little evidence that this works. More research is required.
Protein and Amino Acids
Both are widely used by body-builders wishing to "bulk-up." Nutritionists claim that normal dietary intake is sufficient. Some dietitians claim 1 gm/kg of body weight per day is all that is needed, whereas a German scientist (Stegeman) has reported that double that amount is required. [A general rule-of-thumb is that an appropriate diet would include 15% protein.]
Most athletes probably have adequate intake of protein if they are not vegetarian. There is likely to be little benefit derived from excess ingestion of protein and/or amino acids.
This is a banned substance over a set blood level. Recent research has shown that any level of caffeine, including below the illegal limit, can improve performance. The amount is not relevant to performance.
Caffeine works because it increases the use of fat as an energy substrate and thus, spares CHO. It is also beneficial for events up to five minutes because of its stimulatory effects.
It is likely that caffeine will be banned completely or totally deregulated.
Creatine is involved in the regeneration of energy (adenosine triphosphate - ATP). Its availability limits performance in short explosive activities. The administration of 5 gm doses over five days will significantly enhance muscular performance and enhance recovery. Some research suggests that it may allow athletes to train with reduced fatigue at an intensity higher than normal.
This is intended to increase the buffering capacity of the blood and thus, delay the onset of debilitating levels of hydrogen ions and lactate. Increased blood acidity inhibits glucose oxidation and energy production.
If 0.3 gm/kg of body weight is ingested, speed performances are benefited. However, the frequent side-effects of gastro-intestinal distress warrants thorough experimentation before it is tried in competitions.
Carnitine's main function is to transport fats into muscle tissue for energy provision. Supplementation does not increase performance or enhance fat burning although it may correct deficiencies in some persons.
The following ergogenic aids are suggested by the literature.
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