Five full days after we've started our little private study, we've seen an interesting occurrence, and have also had our first heated discussion on how to interpret what we're finding.
First, the good news: I've noticed a definite reduction in hyperactivity over the past five days, even on the days that Gus didn't really go out and burn off any energy. He hasn't been lethargic, and there have been brief, minor spurts of bounciness. Then yesterday, we gave him one of those fruit bars (like a Nutrigrain Bar, but with unprocessed sugar) that had about fifteen grams of sugar and just before that he had two oatmeal cookies with about nine grams of sugar. We were at the beach and the kids have gotten into the habit of having cookies for their snacks when we're there (not provided by me, by the way). About two hours later, he was zooming through the house like the Concorde, and that lasted for at least an hour.
I took this as a pretty clear indication that the large amount of sugar revved him up to that manic state, but my husband seems to think that it's inconclusive and we'd need to give him a big dose of sugar again to see if we get the same results. I can see the logic in that, but I don't think that getting Gus excessively worked up, just to see what will happen, is an acceptable idea. Hubby thinks that an hour of manic behavior (which by the way can also be dangerous for Gus - he often runs and slams himself into the wooden or glass doors, or starts jumping and climbing on chairs) isn't the end of the world. Maybe not, at least until he breaks the glass or goes sprawling on his face and ends up in the emergency room.
so, we continue to observe. I've got to find some snacks to take with us later this week for our visit to the water park, because I know it will be a challenge to keep him from all the crap that will be available. Wish me luck.