The most common cause of disability -- and how to avoid it

Healthy aging is about more than growing old without heart disease or dementia. It's about growing old without losing a step -- growing old and being able to continue to get out, get around and do the things you love.

It's about being growing old and keeping your independence.

But for millions of seniors, healthy aging is just a dream -- and life itself has become a nightmare. They're in constant pain. They can barely stand, much less walk -- and many need help with the basics of everyday life.

This is the toll of arthritis, with new numbers from the government showing more than 50 million Americans suffering from the disease -- and 22.7 million of them are battling disability because of it.

These are numbers no one expected to see -- not now, and not yet anyway. In fact, the CDC recently predicted 22 million people suffering from disability due to arthritis -- but not until the year 2020.

We're nearly a decade ahead of schedule -- and the main reason for it, of course, is the obesity epidemic.

Obesity is a leading cause of osteoarthritis, especially osteoarthritis of the knees, for the simple reason that our joints were not designed to support the amount of weight people are putting on them.

That's why the new numbers show that nearly a third of the obese have arthritis, and 15 percent are suffering from disability due to the condition.

The clear answer, of course, is to lose some weight.

If you don't have arthritis yet, weight loss just might help you avoid the condition completely and bring you one step closer to healthy aging. And if you're already suffering from the toll of arthritis -- even if you're practically crippled by it -- losing weight can ease or even eliminate the pain.

One study I told you about just last month found that losing just 10 percent of your body weight and getting a little exercise three times a week could ease the pain of knee osteoarthritis, reduce inflammation, improve mobility, increase function and improve your overall quality of life for healthy aging.

And if you're willing to lose even more weight -- and get even more activity -- you could see even bigger improvements.

I'm not done with arthritis yet. Keep reading for the latest on rheumatoid.