Depending on which type ADD child you have, sometimes encouraging too much physical activity is a mistake and can have the total opposite effect because it is too stimulating and they have a hard time coming down from that. These kids need activities that will help them to hyperfocus not get hyper. LOL!
Building toys like Lego, intricate puzzles, seek and find books, reading (topics they care about of course) crafts, or other highly focused activities are a good way to get them to chill out. The key is that it must be something they're interested in and something that requires alot of thinking and focus. This is why Martial Arts is always recommended as an ideal sport for kids with ADD. It is both phyiscal but very purposeful and focused.
Yes, these kids need physical activities, but they have to be the right kind.
Be careful with fruits and dairy as another poster mentioned. Dairy is one of the biggest culprits of behavioral disorders in many kids with undiagnosed food sensitivities and allergies. A good alternative is coconut or rice milk products (there is rice and coconut ice cream, cheese and yogurt too and it tastes great). Soy, goat, Kefir, and even raw organic cows milk can be problematic for kids with dairy or other food sensitivities.
Often if your child is actually allergic, he's suffering from yeast overgrowth and that can make them act pretty crazy. For these kids, not only is dairy bad news, but so are whole-grains and breads. They have gluten and that feeds the yeast as does the sugars in milk products. And that can make your child have serious behavioral issues. If yeast overgrowth is playing a role here, you should avoid any grain products that have gluten. Rice and corn based crackers, breads, etc. are your best bet as they do not have gluten. You might want to look into supplementing with acidolphilis chewable tabs for kids, grapeseed extract, and omega-3s. These can do wonders. Just google yeast over growth and attention disorders and you'll find plenty of information and resources. A product that covers the omega-3 supplementation that is sold over the counter that you might want to look into is liquid "Calm." You can find it at most big chain vitamin shops.
Some fruits are very high in sugar and can have negative effects on kids with borderline glucose issues. Any chance glycemia or diabetes runs in the family? If you're not sure it might not hurt to have your doctor look into this.
You might be surprised to find out the allergy tests done in most pediatrician offices DO NOT detect food allergies very well. You need to look into tissue testing and may need to find an allergist to get the right kind of testing done.
An elimination diet is a quicker way to find out if he's allergic to dairy or has senstivities. Sounds like your doctor doesn't buy the whole diet approach for attention disorders. Some don't. I say don't be afraid to go to a specialist who is pro alternative medicine and see if it will work for you. Otherwise your only option will eventually be to go the medication route. Nothing wrong with that if that's what works for you, but there are so many families out there who have had great success sticking to a diet aimed at tackling hyperactivity and never have to go the drug route. I say research amazon and get books and resources that detail specific ADD diet plans and give it a try. The Feingold diet is a good one. They can work for some people.