Hi Suzanne,
I would definitely try the mid-morning protien snack. If his behavior is that goofy that consistently at that time, it really does sound like he needs a snack.
The other thing I would recommend, as both a jr. high/high school teacher and a mom of two very high-energy (although not ADHD) sons, is to pop in and visit his classes (particularly the 11am one, when he seems to be at his worst). My youngest was in 2nd grade and his teacher complained constantly about my son's behavior. Frustrated beyond belief, I started to drop in to check things out for myself (unannounced, of course). Imagine my surprise to find out that, while an excellent teacher, this teacher's style didn't work for my son AT ALL. Her class rules, norms, everything, were the exact opposite of what my son needed to be successful.
As a classroom teacher, I generally give all my sons' teachers the benefit of the doubt. If I had not seen what I had seen with my own eyes, for a month of visits, I would not have believed that it was the class environment, not my kid. What I should've done was transferred my son to another class. I did not and have regretted it ever since. You may discover that the issue is less your son's ADHD and more of a classroom environment issue (not that the environment is bad, it just doesn't work for you son).
Does your son have an IEP or a behavior contract through the counseling office? While most people see these things as a negative, they can be an excellent tool to compel recalcitrant teachers to try different styles and techniques with your son, as well as letting your son know you're serious about good behavior.
Last but not least, 8th grade is just a squirrely year for everyone. I've never had an 8th grade class that wasn't climbing the walls right before lunch. This isn't to excuse your son's behavior, but a reminder that it could just be a phase he'll outgrow. Any way to get him into gym class right before lunch? <wink>
As for diet, I'm sure you already avoid high sugar breakfasts. With my high energy 5th grader, we focus on high-protien breakfasts with fruit. It's really made a difference.
Good luck!