There is a hierarchy of problems in our illness. Treating one thing (like leaky gut) is not going to get you far if the top of the food chain reason is not taken care of. Which could be heavy metals toxicity in the brain, mold in the brain, an infection or virus, a parasite, etc.
The reason why I buy into it is because I have gotten huge shifts in my symptoms from not being able to exercise at all to playing in a flag football game, yet my level of suffering has not changed.
This is because whenever I improve physically, my brain gets cognitively messed up and I get autistic symptoms. So I think that the core illness is not taken care of, heavy metals and neurotoxins in my brain.