The question would be: Which one would be the cause and which one is the effect?

I am diagnosed with ADHD and I consume unhealthy amounts of sugar in form of chocolate, gummy bears and ice cream. I wonder if...

A) all that sugar creates a gut microbiome that facilitate ADHD symptoms or if

B) the general impulsiveness and higher-than-usual glucose demand from the brain create the sugar cravings, or if

C) it's some kind of feedback loop and bad habits get reinforced to the point of addiction