You know about America's obesity epidemic. You've likely seen news footage of fat American torsos waddling through a generic streetscape as an announcer intones the alarming statistics – that 36 percent of U.S. adults are obese. And you've probably also heard about sickness that can spawn from obesity such as heart disease, stroke and diabetes. But there's another consequence to this crisis that, while lesser known, is no less dangerous. It's called nonalcoholic fatty liver disease or, simply, fatty liver – and it sounds like what it is.
[Read: Our Titanic Obesity Problem.]
"They generally are a little bit swollen, and they look fat ... They don't look too good," says Don Rockey, chair of the department of internal medicine at the Medical University of South Carolina. But unless you're looking at your liver, you probably wouldn't know if it had turned yellow and bloated from excess fat. And that's precisely the problem: Most people never realize they have the malady unless it's spotted on an ultrasound or blood test or when it's progressed to such an advanced point that symptoms occur.
"I think a lot of people are walking around with liver disease and don't know it," says Kymberly Watt, medical director of liver transplants at the Mayo Clinic in Rochester, Minn.
As much as 35 percent of American adults and 15 percent of children have fatty liver, and its prevalence is largely linked to the growing rates of obesity, diabetes and lipid problems, according to Naga Chalasani, director of the division of gastroenterology and hepatology at Indiana University's School of Medicine. In most patients (up to 80 percent), the condition won't cause problems, he explains. But in the rest of the patient population, it can develop into nonalcoholic steatohepatitis, an inflammation of the liver, which can lead to fatal diseases like cirrhosis.
A scarring of the liver tissue, cirrhosis may be caused by hepatitis, alcohol abuse or, as discussed, fatty liver disease. In any case, it renders the liver dysfunctional and thereby requires a transplant to continue the organ's vital work of filtration in the body.
About once a week, Rockey says he will see a patient with complications from cirrhosis as a result of a fatty liver that went undiscovered. "The process smolders for years and years and years," Rockey says of the patients in this situation. "They didn't know they had a problem, and boom – they show up with cirrhosis." While Hepatitis C is currently the leading cause of cirrhosis in this country, fatty liver is projected to quickly overtake it, he says. "This is an epidemic in the United States that is attributed to our lifestyle, and we can thank McDonald's and all the fast food and unhealthy joints," he says.
Unless the disease progresses to cirrhosis, fatty liver can be prevented and even reversed by losing weight. "Weight loss is the key, and it doesn't have to be gigantic amounts of weight loss ... every bit helps for sure," Watt says. She advises that people strive for a body mass index below 25, the benchmark for an overweight diagnosis, according to the Centers for Disease Control and Prevention. She also stresses the importance of controlling cholesterol levels and, for those with diabetes, managing blood sugar. People with risk factors such as obesity and metabolic syndrome should also be screened for fatty liver, Watt says.
"What I tell people to do is take care of themselves," Rockey says, stressing the importance of a healthy lifestyle for preventing fatty liver. "What any good physician tells their patient is: Eat a healthy diet; don't smoke; exercise regularly ... I think it's as simple as that."