Some CFS and other autoimmune conditions may be caused by Endocrine disruptors. “Endocrine disruptors are chemicals that may interfere with the body’s endocrine system and produce adverse developmental, reproductive, neurological, and immune effects in both humans and wildlife.” [National Institutes of Health] “Endocrine disruptors can:
- Mimic or partly mimic naturally occurring hormones in the body like estrogens (the female sex hormone), androgens (the male sex hormone), and thyroid hormones, potentially producing overstimulation.
- Bind to a receptor within a cell and block the endogenous hormone from binding. The normal signal then fails to occur and the body fails to respond properly. Examples of chemicals that block or antagonize hormones are anti-estrogens and anti-androgens.
- Interfere or block the way natural hormones or their receptors are made or controlled, for example, by altering their metabolism in the liver.”[National Institutes of Health]
Epigenetics is the turning on or off of DNA due to environmental influences such as the endocrine disruptors. This means that the complexity of treating some conditions is far from trivial. In terms of classic CFS research, Dave Berg’s work on hypercoagulation (too much coagulation) could be associated with endocrine disruptors impacting control of coagulation.
Thyroid issues are common with CFS, with naive treatment of this symptom in isolation of the panorama of other associated symptoms being too common. Our knowledge is very limited, researchers state that these complexities “render human studies very difficult”. A few of the known or strongly suspected disruptors include:
polychlorinated biphenyls or PCBs 
- Between 1865 and 1914, large amounts of PCBs were released into the environment, to the extent that there are still measurable amounts of PCBs in feathers of birds currently held in museums [Wikipedia]
- as late as 2013, PCB contaminated sewage was found on farm land in the US. Some crops may have been feed to chickens exported across the US.
- “The study showed that exposures from phthalate-containing medications can far exceed population levels from other sources… they are used as inactive ingredients in producing enteric coatings [on pills]”[wikipedia]
- Phthalate parent compounds and/or their metabolites have recently been implicated as a cause of breast cancer[wikipedia] 
- bisphenol A (BPA), 
- brominated flame retardants 
- perfluorinated chemicals 
- triclosan (TCS) 
- parabens 
- phenols 
- added to plastic packaging on food
- named Contact Allergen of the Year 
- organotins 
- Lavender and Tea Tree Oils 
“A high individual exposure to one chemical was often associated with a high exposure to other of the chemicals and the possibility of combination effects of multiple simultaneous exposures…. 100-500-fold higher than the median level were seen in some participants.” 
What to do?
The ideal first thing is to get measured for your levels of the known disruptors. This can be a challenge because most of the results were done with research test. There is a lot of literature [NIH][EPA] on how to determine if a substance is a disruptor as well as citizen-science initiatives. There are significant problems with getting a clinical lab to accurately test even some of these chemicals (and even thyroid levels are a problem to test). There appears to be only a single lab claiming appropriate testing across a range: NMS labs. Genova Diagnostics offers some testing of BPA via urine sample. Reduction can present a challenge. Some of them appear to be reduced by fasting, but that also means that after the fast, extreme care need to be taken to not re-introduce them. Some, like PCBs and dioxin’s, are prone to concentrating in fat and may require alternative approaches, for example, Olestra has been shown to be unusually effective in removing these   . Colestimide has been effective in another study . Olestra is preferred as it does not require a prescription, and is used in certain brands of potato chips(labelled as Olean chips). Personal experience with several people that are chemical sensitive has been much faster recovery and less symptoms using Olestra after a triggering exposure (although there was resistance eating these “gross chips that produce smelly farts”).
- “Grains, flour and dry mixes and total fish consumption were positively associated with BPA… Non-fresh vegetables and poultry were both positively associated with BPA” , i.e. reduce
- “phthalates were associated with consumption of certain foods (i.e. chocolate and ice cream)” – note that this is standard commercial products being cited. For craft products, be very careful they may use contain these chemicals still.
- “We observed that fasting status significantly affects the concentrations of MEHP, MEHHP, MEOHP, and MCPP metabolites analyzed in this study.” 
- “phthalates were higher among mothers and children… due to higher presence of PVC in floorings and wall coverings 
- “statistically significant (p<0.05) positive associations in boys for cologne/perfume use… girls for colored cosmetics use… conditioner use… deodorant use… and other hair products.. We demonstrated that personal care product use is associated with exposure to multiple phthalates in children.” 
- “Urinary concentrations of MEP[monoethyl phthalate] showed a positive relationship with the number of personal care products used” 
- the use of a few specific products including liquid soap, hair care products and sunscreen was positively associated with urinary concentrations of some phenols or phthalate metabolites.”
Alternative Heath Suggestions
The typical suggestion is for a “cleanse” of some form. It is a panacea treatment for almost everything with roots in religious beliefs: ” You are ill because you need to cleanse your soul and your body” and is often religiously believed by some alternative health practitioners. My typical attitude is simple: “show me the peer review studies showing that this specific cleanse is effective for this specific study?” I agree with Harvard Medical School and researchers who tried to find any supporting evidence for any conditions. With that said:
- Yes, fasting (or any type) appears to reduce these disruptors, it is simple to understand: the body eliminates toxins naturally and ongoing. Stopping the addition of new disruptors by not eating will drop the level
- Chinese herbs for nourishing Shen-yin and removing Xiang-fire (NYRF) may be effective 
Many endocrine disruptors come from food wraps. The longer that the wrap is on something, the more the disruptors will leach. Avoid food packaged in boxes (which will often be coated on the inside) or in plastic containers. Avoid anything which has a emulsifier (often ice cream, many chocolates). Eating out may be a high risk activity.