Thinking about that migraine post reminded us of our current theory that the reason gluten free caught on as a fad is because there's a ton of people with undiagnosed celiac. Because the facts are:
The cause of Celiac disease was discovered in the 1940's previously it was a death sentence, usually in infancy for severe cases or teenager for less severe
There is a strong genetic component to its development
The time from symptom onset to diagnosis is often years, and in many cases is over a decade
The stuff attributed to the diet; increased energy, less bloating, improved digestion, helping mood and cognition, decrease in pain and more; are all also common symptoms of Celiac disease
Taken all together Celiac is a highly heritable disease where those affected have only been surviving into adulthood and thus having children for a few generations, leading to a huge increase in the population vulnerable to it in a relatively short time, with an extremely long time between symptoms emerging and diagnosis, and pretty much everything the GF diet claims to treat will work, if you actually have Celiac Disease.
Of course there are tons of people who swear it works for them, because it did! They probably did have their mysterious rashes and fatigue and pain and bloating cured because they had Celiac and being GF will fix that.
The problem isn't they are lying about their experience, its that they were likely dismissed by the medical system, went looking for anything that could help and got sucked into alternative health circles.
We don't think there is any way to address the issue with fad diets without also addressing the fact that there are tons of people with undiagnosed issues like Celiac and other food allergies who are going to try them and get better because those diets are the treatment.
People who are almost certainly going to encounter the diets before they receive any help from the medical system, and receive more support from the communities around said diets then the medical system.