ADHD is commonly inherited, so I'd assume that it's not so much that it's caused by processed food as that the children who eat more processed food do so because their parents lost track of time and reached for the quickest meal (I do this all the time).

I don't cook from scratch, nor would I feed much American food even to a dog. There's a middle ground, which is filled with stuff like frozen baked potatoes (microwave in five minutes), microwave rice and frozen chicken grills.

Like exercise, any step in the right direction is better than none. Some people are just never going to run for 30 minutes a day, but a brisk 20-minute walk will keep you alive for longer.

Go easy on yourself - when you put yourself under less pressure, it's easier to get started.