Non-alcoholic Fatty liver disease has recently been revealed as a growing and very serious public health threat in the U.S. The "silent killer" is related to poor diet, lack of exercise, and obesity; patients often do not experience symptoms for years.

A patient named Renee Terney was diagnosed with the disease two and-a-half years ago after she almost died from the accumulation of fat in her liver cells, McClatchy DC reported. Terney, who is now 48, has since lost 85 pounds.

"My goal is not to put it back on," she told McClatchy DC.

If the disease is caught early and diet as well as exercise habits are improved it can be reversed, but in many cases the condition is not noticed until it's too late. The condition is often discovered when routine blood work reveals elevated levels of liver enzymes. There are currently no treatments for the disease other than behavior modification.

Fatty liver disease is usually asymptomatic, but it can cause symptoms such as fatigue, pain in the upper right abdomen, and weight loss, according to Mayo Clinic.

As the disease progresses symptoms such as "belly pain, jaundice and swelling of the legs" can occur, McClatchy DC reported. Once the condition reaches that point the patient's survival relies heavily on a transplant, but livers can be hard to come by.

Of the 17,000 people on U.S. waiting lists only about 6,500 receive transplants every year; 15 percent of the remaining patients die before receiving a transplant. Non-alcoholic fatty liver disease is "the most common liver disease in most of the Western world," according to the American Liver Foundation, McClatchy DC reported. The disease affects 30 million Americans and the numbers are only climbing.

"We are particularly concerned about the high prevalence of fatty liver disease in children. It is setting them up on a path to liver failure and puts them at significant health risk," foundation Chairman Tom Nealon said, McClatchy DC reported.

Obesity has been on the rise in recent decades, and is the main risk factor associated with the disease.

"I think it's very, very important that people recognize that obesity can shorten life expectancy, and, conversely, longevity has been associated with thinness," Vinod Rustgi, medical director of liver transplantation for UPMC said, McClatchy DC reported.