Our leading killer remains what it has been every year since 1900 -- heart disease.

It kills nearly 650,000 people each year, and we can only blame ourselves.

Our own bad habits -- smoking, no exercise and fat-ridden diets -- are the main causes of heart disease.

But did you know you can reverse the damage that's been done?

Pattiy Hill was 51-years-old and fading fast.

She was a yo-yo dieter who rarely exercised and was diagnosed with diabetes and high blood pressure.

"I had been fat for so long. I wanted to live, and I knew fat people don't grow old," says Pattiy.

At 280 pounds, Pattiy wanted a do-over.

"If you quit before age 35 and before 20 pack years -- which is one pack for 20 years -- you get all of it back," explains Doctor Michael Roizen of the Cleveland Clinic.

From changing your lungs to changing your genes, eating three quarters of a cup of broccoli four times a week turns on the GSTM-One gene. That gene makes a protein that kills prostate, breast and colon cancer

"You get to turn on a gene that helps you kill those cancers simply with something as simple as having broccoli," says Doctor Roizen.

12 walnut-halves a week doubles the amount of omega-three that most of us have.

"It decreased the risk of stroke or heart attack by 62 percent," adds Doctor Roizen.

Diet and exercise also takes the years off. Pattiy has lost 136 pounds the old-fashioned way. In 13 months, she cut her body fat from 60 to 20-percent and went from a size 24 to a slender size
four.

"I looked at it as a way to help myself rather than a way of depriving myself," Pattiy says.

If you're using money or insurance as an excuse, think again.

Pattiy lost all her weight while she was uninsured.

The only money she spent was on a gym membership, and the savings on her medications she used to take has more than paid for that.