I just can't believe the number of articles written on such a simple topic. No need for books or secrets folks, it's easy as pie. As a father of two, both are physically fit. How?  I pay attention to them. I feed them healthy food with snacks in moderation. I put them in sports activities using funds from their Canada Child Benefits. I go outside and play with them.  We go for walks with the dog, hiking, and go to the park.  It's not rocket science folks. It's just not. Pay attention to your kids, feed them healthy food, and go outside and your kids will not be obese. If they still are, go to the doctors cause it's something health related. Their, no charge. Your answer in one short paragraph. And if you're trying to make health excuses not to go outside with your kids. Well, I have a disability from my military days, and I still go outside. It just hurts, and I deal with it. That's being a parent.