I am also sceptical. You could only ever be sure if you had an honest assessment of diet before and after change and symptoms, otherwise it is far too easy to think that something is making a difference when in fact it isn't.

That being said, it is reasonable for anyone with a bad diet of junk food and fizzy drinks to sort out their food choices.

For me I got the first symptoms only 10 years after I had switched from junk food and beer to healthy food, including vegetables. The only thing that I changed just before getting symptoms was stopping coffee. I have since returned to drinking coffee, but my symptoms have not improved.