Even while I was sick my energy level improved from about 30% of normal to around 70% when I stopped eating foods high in sulphur, but that's a sensitivity, not an allergy. One of my symptoms was that I kept developing more and more allergies, especially to foods. But avoiding them isn't what made the big difference.
When I reached menopause my doctor said I was at high risk for osteoporosis, partly because of all the cortisone that had been given me. But all the HRT pills contained cornstarch and one of my worst food allergies is to corn, so the doctor gave me an estrogen injection instead. When I went to fill the Rx for the only progesterone I could have the company had just stopped manufacturing it, so I couldn't take any progesterone with the estrogen.
I had horrendous side effects from that injection for eight months, but at the end of that time my CFS symptoms were mostly gone and the asthma I hadn't had since reaching puberty had returned. I'm not sure which happened first, so it could be that the asthma meds, which are cortisone-related, helped with the CFS symptoms, or maybe the changes in my other hormone levels caused the asthma to return. But my CFS couldn't have been caused by an endocrine imbalance in the first place because all my hormone levels had tested as normal. And some PWCs have asthma and use those meds without their CFS being helped by them.
I have read that sulphur is part of the chemical makeup of many hormones, so there may be some sort of connection there.
No doctor is likely to give anyone else an estrogen injection without also giving them prednisone because it's dangerous. Since men also get CFS, an estrogen imbalance obviously can't be the cause, but some sort of hormonal confusion that doesn't show on the usual tests might be.
I tried the sulphur-free diet because a friend of mine with lupus had been put on one by her doctor because it was known to improve lupus symptoms. When my friend noticed that some of my true allergies (oranges and tomatoes) were on that list she gave me a copy and I tried following the diet. As I told you, it helped a lot within a few weeks. Lupus is an auto-immune disease so there could be some sort of correlation with CFS.
A survey of an internet support group for PWCs showed nearly all of them had a virus known to cross the blood-brain barrier and another major illness or injury within a few years. Apparently having both the virus and something else attack so close together set off something in people's bodies or brains (somebody suggested it might be the hypothalamus) that has never been able to shut down again.
But, in my case, the estrogen injection overcame it.
Although I feel fine now except for the multiple allergies, if I eat anything high in sulfur my CFS symptoms return mildly. I won't eat those foods long enough to find out if continuing to eat them would make me worse, for obvious reasons.
I wish some scientist would use my experiences to help figure out a cure that would work for everyone, or at least be able to explain what causes the disease.