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This summary is from the IAAF 2nd International Consensus Conference on “Nutrition for Athletics“ held in Monaco from April 18-20, 2007. Copies of the CD and booklet are available from the IAAF website www.iaaf.org.
Innovations in Training and Nutrition
Presenter: John Hawley (AUS)
The “train low, compete high” paradigm of glycogen levels has been challenged by a new study that shows no benefit of training in a low-glycogen state. Although some genes involved in training adaptations were enhanced after training in the low glycogen state, this does not mean athletes should adopt the practice. It could have deleterious effects on the ability to train hard and recovery from training, could be a possible risk factor for overtraining and could impact the immune system. Training in a low glycogen state is not recommended for strength training, as there is a proven negative effect on gene expression. It was noted that in practice, many top distance runners do an early morning run in a fasted state.
Athletes are advised to consume about 10 grams of protein in the early «3h) phase of recovery to improve net protein balance. Some discussion took place about the role of muscle catabolism after exercise and that there might be some rationale for not dampening the catabolism by adding extra protein. No effect of extra protein on muscle glycogen is to be expected when ample CHO is provided. The addition of protein in a CHO drink during exercise remains equivocal. It seems that when enough carbohydrate is provided, the addition of protein is futile. There is no generally accepted mechanism for the added protein to have an ergogenic effect.
Athletes training at altitude should have their blood iron parameters measured about one month before their training camp. In case of deficiency, iron stores can be replenished before departure. No iron supplementation should be given without an indication of deficiency.
The anorexic effect of altitude can have a negative effect on energy balance. Strategies to improve energy intake include increasing meal frequency and decreasing protein intake. Protein is highly satiating and induces more thermogenesis than the other macronutrients. Therefore, low protein intake can enhance energy intake. Negative protein balance is worsened by an energy deficit. Increasing meal frequency is advised.
Oxidative stress is enhanced in altitude training. There might be some rationale for the use of extra anti-oxidants. Foods that contain anti-oxidants are advised. The use of supplements remains controversial, since it might inhibit training adaptation, and act as pro-oxidant in high dosages. Athletes should not use bicarbonate at altitude, since it might induce acute mountain sickness. Altitude exposure induces higher fluid losses. This should be balanced by a higher fluid and sodium intake. The role of omega-3 fatty acids remains equivocal.
The above summary was written by Peter Res
If you wish to download this handy Grams and Calorie Calculator for Carbohydrate, Protein, and Fat, click here for the Excel spreadsheet.
This is part 12 of 14 in a series from the 2007 2nd IAAF International Consensus Conference “Nutrition for Athletics”
Jimson Lee
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