Repeated days of hard training typically result in an accumulation of fatigue, making it more and more difficult to complete the workouts, that would be no problem in a rested state. This is a very common scenario in a training camp. Even within 7 days, athletes can develop symptoms of overreaching and it may take 2 weeks or longer to fully recover. How can the diet influence this? How does a higher carbohydrate intake help?
For more information on overtraining see: Overtraining is it real? The symptoms of overtraining, Symptoms of overtraining and Causes and prevention of overtraining.
Influence of diet
The composition of the diet is one of the key factors that determines the recovery during overtraining periods. In 1992 we developed a protocol to induce a state of overreaching in well-trained athletes and used this protocol successfully in a number of studies since then. We started to learn more about the symptoms and the time line in which performance reductions and other overtraining symptoms develop. An important practical question was: can this be altered (improved) by diet? Can we prevent the symptoms by feeding more carbohydrate for example?
The composition of the diet is one of the key factors that determines recovery during overtraining periods
In a study published in 2004 (Dr Juul Achten was the first author of the paper) we simulated a training camp situation in runners. For 7 days the runners trained extremely hard and performance seemed to deteriorate over time. Runners also developed various other symptoms of overreaching; most notably changes in mood state. Although some runners seemed a little more fatigue resistant then others, by the end of the week all runners displayed deterioration of performance and changes in mood state.
How was diet manipulated?
These runners performed the same intensified training period twice, with a 10-14 day period of rest separating them. In random order the runners received a normal carbohydrate diet containing 5.4 grams of carbohydrate per kilogram body weight per day (g/kg/day) or a higher carbohydrate diet. A diet of 5.4 g/kg/day is a very common carbohydrate intake for endurance and other athletes. The high carbohydrate condition consisted of 8.5 g/kg/day. This is a high, but not extreme carbohydrate intake (often carbohydrate intake recommendations exceed 10 g/kg).
What was the effect of the different diets?
It was obvious that the high carbohydrate diet improved the situation. Performance still