Adrenal fatigue can be an underlying cause of overtraining syndrome, an umbrella term used to explain a decrease in performance and motivation. If left untreated, adrenal fatigue can spin your hormones out of whack, making you feel tired, depressed and lacking the energy you need to get on the bike to train.
Fortunately, you can improve your adrenal health by recognizing the symptoms and changing your diet.
We have 22 Nutrition Tips to Help Cyclists Recover from Overtraining, here are 5 of them:
1. Eat a nourishing whole food snack.
Eat a nourishing whole food snack before 10 a.m. to replenish low blood sugar from a night of fasting. Examples of acceptable snacks include nut butter, oats, lemon juice and water or poached eggs.

2. Have a snack that includes protein.
Have a snack that includes protein, fat and carbohydrates between breakfast and lunch.

3. Avoid fruit juices.

4. Drink vegetable juice.
Drink 4 ounces of vegetable juice with a pinch of salt with a main meal.

5. Use sea salt.
Use sea salt on your food.

... more tips can be found in this article: http://www.active.com/cycling/articles/22-nutrition-tips-to-help-cyclists-recover-from-overtraining.
And if you have more useful tips, just reply this post.