I am not aware of any research of fasting for ADHD but in my opinion it will help enormously in one of two ways.
Firstly, it will cleanse the Brain of any morbid toxins/plaques and other impurities: this will result in much greater clarity of mind/much improved memory and other cognitive issues............................
and secondly after your fast, I would target your Brain and nervous system with specific nutrients, and where both measures combined, will in all probability, eradicate the condition entirely.
Which nutrients though?
I have no affiliation with this company, but a product on the market called "NEUROZAN" is formulated for Brain and Nervous system health. I can vouch for its efficacy as it was the one single product (out of many that I tried) that cured my Severe Depression
of years standing, and which I still take to this day. The results are very noticeable if I do not take it on a daily basis.
I would also strongly consider these supplements.......
#1. DHA(docosahexaenoic acid)
#3. Alpha-lipoic acid.
#4. Dimethylaminoethanol (DMAE)
#6. Vitamin D3 (5000ius per day)