Posted as a comment, and unexpectedly it became an essay, processing thoughts I've had over the last few years regarding diets undertaken to address particular medical conditions.
A related issue to obsessive consequences of "clean eating" is that certain diets for particular health conditions are extremely difficult to undertake rigorously, sometimes requiring careful control of variables, and causing significant side effects that can temporarily derail work and family commitments.
A large proportion of people who begin difficult diets will drop out because of the sheer effort of adhering to them properly. See for example, this 2012 article, "Long-term dietary intervention trials: critical issues and challenges."
I was very lucky that my worst health problems arose at a time when I was writing a thesis so I did not have a strict employment schedule, I was able to experiment with diet based treatments, undertaking them methodically and staying in bed when I was wiped out by them.
In particular, undertaking a low carbohydrate diet such as the specific carbohydrate diet (SCD), for inflammatory bowel disease, or the Low FODMAP diet for fructose malabsorption, or detecting a food intolerance through the elimination diet, will certainly cause several days of exhaustion due to bacterial die-off (Herxheimer reaction). [I have experienced this with all three].
As a result, and sometimes as a result of inadequate nutrition, I have occasionally experienced excessive weight loss and worry from family members, despite their overall positive lessons for me, leading me to reduce my inflammation levels: I am now able to control my symptoms mostly without drugs.
Our families [and perhaps employers] should understand that they need to give the right kind of critical support to our efforts to understand our food intolerances and the dietary aspect of our medical conditions. Many people are frustrated in their messy attempts to know their own food needs in ways that may yield long term benefits to their health, especially since the science behind some of these diets is underdeveloped.
We need to distinguish between obsessive behaviour that requires intervention, and the valid careful and dedicated adherence to a particular diet until it yields results.
However the difficult truth is that sometimes there is a fine line between the two because when we are trying to find a food culprit for our symptoms we can become invested in our particular hunches, and become almost superstitious, noticing every negative symptom or mood swing and demonising particular foods as causing it when they in fact have not.
To reduce this confusion and worry from family members, I undertook the low FODMAP diet with a dietician's supervision. Part of the reason was that it had more peer reviewed studies backing it up than SCD for example -although SCD now has some peer reviewed support - see here.
Yet I do not think that Low FODMAP was necessarily more effective for my situation. While I have benefited from excluding wheat from my diet for 15 years, suggesting the validity of the category of "wheat fructans," the category Polyols including mannitol that mushrooms are part of in the FODMAP framework does not seem to be an issue for me: I can happily eat sweet potato and sweet peas, yet I cannot eat mushrooms or chewing gum sweetened with mannitol. I have now excluded mushrooms and chewing gum permanently, reducing my headaches, digestive distress and exhaustion.
Working with the dietician did however help me in being more rigorous, keeping a more methodical food diary and also being less absolutist in my adoption of some aspects of the diet.
I also later found that some other foods cause problems for me. Legume-based additives such as guar gum and carragenan cause terrible side effects for me, while lupini beans and lupin flour make me sick. Perhaps this is due to particular plant chemicals that function as defences against herbivory, with some legumes having higher concentrations because they do not have long histories of domestication that other legumes such as lentils (which are fine for me) have. Some emulsifiers as well as brewers and bakers yeast also cause problems for me.
None of these diets has in itself produced the magic cure I was after, yet each has taught me something new that I have carried forward that has benefited my health greatly. Each has also taught me to be attentive through practicing a food diary.
The trouble with the diagnosis of “orthorexia” nervosa is that is can lead doctors and other authority figures up the familiar path of psychologising , of saying “it’s all in your mind,” which today we have a name for: gaslighting.
Now as we are in the revolution of the microbiome, we simply cannot say "it's all in your mind" anymore. As neurology has given us the extended model of the brain, and shown how mind and body are connected, we no longer accept reductive explanation, and the medical practitioner has to at least admit that they do not know the extent to which food is part of our maladies of chronic disease, and that they cannot moralise about healthy eating when what is healthy for one person may not be healthy for another.