I take medications (immunosuppressants) which fatigue me terribly, especially when riding... the only remedy I've found is to shovel brocolli and pasta into my mouth the day before a ride, then take a day off, eat like a horse, ride the following day.. it doesn't cure it, but since my body feels like it's using double what a normal rider would due to the fatigue, I make sure I'm eating the proper carbs and staying away from all unhealthy sugars and fats... this includes popping probably twice the gel packs that someone else would during a long ride.
Nutrition, as flawless as you can make it, will help, in my opinion. I bonk hard if I don't eat right... last wed I bonked after 15 miles (usually do about 40 miles, 3-4x a week)... bonked so hard that I had to leave work that night because I was ready to pass out (didn't eat much for a couple days prior to riding - not smart)... I ate nothing buy veggies and pasta for 2 days and then on sat did 55 miles without tiring one bit... didn't even stop.. kept a 19mph pace too.
I know this may not be specific to chronic fatigue syndrome, but due to the meds I'm on, you can basically say I've got self induced fatigue
... necessary for me though unfortunately.
Good luck finding a way to treat it... eat some brocolli and pasta
... and of course, consult a doctor or maybe a nutritionist to get you on a proper diet.... also, as with any illness, keeping your body as clean as possible is key... drink TONS of fluids - water is the best... and I mean TONS OF IT... I find that apples are excellent in cleansing the digestive tract too... the old saying, an apple a day yada yada has a lot of truth to it. Keeping the digestive tract moving and clean helps to prevent toxins from building up and getting into the blood stream, which is obviously very important.