Many athletes make the same nutritional mistakes that can lead to overtraining rather quickly. An important nutritional concern is consuming an adequate amount of calories. Many athletes underestimate how much food they need to eat to support their intense training regimen. This will lead to possible weight loss and decreased physical performance.
This is similar to requesting that your car travel 50 miles when you provide it enough gasoline to travel 20 miles. Some athletes seem to have a carbohydrates phobia due to false beliefs that carbohydrate is responsible for weight gain.
Other Factors:
Proper nutrition plays an important role in preventing overtraining, but there are a few other factors as well. sleep is very important for recovery as it is the time for your body to recuperate from strenuous training.
The optimal amount of sleep per night would be 8 hours or more. Many athletes also train too hard and long as this can be counterproductive (Halson).