Two years ago Kari Roberts of Crestwood, Ill., weighed 320 pounds.

Aware that obesity could lead to diseases like diabetes and heart disease, she knew she needed to lose the weight. But she'd always lacked the incentive -- until her brother, Tony Bolda, was diagnosed with kidney disease.
    
Bolda needed a kidney transplant and as his sister, she was the ideal donor. But doctors wouldn't allow it.

"The minute I found out he needed a kidney I right away wanted to be tested, but he informed me that they wouldn't even consider me at the weight I was at," Roberts recalled.
    
Hearing that news was all the motivation Roberts needed. She changed her eating habits and began exercising more.
    
Two years later and 135 pounds lighter, Roberts was eligible to be tested as a potential kidney donor.
    
In April, she and her brother got the phone call they had been waiting for. The doctors informed them that not only was Roberts a match, she was a perfect match.
    
The surgery is scheduled to take place in the next few weeks. Doctors predict Robert's brother will make a full recovery.