When you gain too much weight, it doesn't just accumulate on the outside of your body. Fat may start to deposit inside, too, within organs such as the liver. 

This condition is called fatty liver disease. Liver cells, or hepatocytes, fill with large fat droplets and can become stressed, damaged or scarred—some even die. Excessive inflammation in the liver called steatohepatitis can then develop and progress to cirrhosis.

“Most people aren’t even aware fatty liver disease exists. Large numbers of people are affected by this disease, and they don’t realize it,' says Wajahat Mehal, PhD, MD, director of Yale Medicine's Metabolic Health & Weight Loss Program. “This is an epidemic that has crept up on us."

At Yale Medicine, if you have abnormal liver test results, we'll look for the potential causes of those results so that we can develop an effective plan to help you make healthy lifestyle changes and lose weight.

Most people who have a body mass index (BMI) over 27 have fatty liver disease. People who gain weight in the abdomen are at greater risk than those who gain weight around their hips or shoulders. This weight distribution in the abdomen is more common among men, putting them at slightly higher risk compared to women. 

Fatty liver disease typically occurs alongside other diseases related to obesity. For example,many people with type 2 diabetes also have fatty liver disease. 

Fatty liver disease is silent at the start, much like high blood pressure. You might have fat accumulating in your liver but won’t know it unless abnormalities appear in blood tests or on an ultrasound. 

It is often discovered incidentally, when tests are taken for unrelated reasons. If blood or imaging tests reveal liver abnormalities, a physician will perform tests to rule out such other common liver diseases as hepatitis B or hepatitis C. Only a biopsy can make a definitive diagnosis. 

No medication to treat fatty liver disease has been approved. But, one thing has been shown to help reverse it: weight loss. "If people lose about 10 percent of their weight, that’s probably sufficient to help with fatty liver,” says Dr. Mehal.

Studies have shown that with a relatively small amount of weight loss, the liver is able to repair itself and regenerate healthy cells.

Weight loss is currently the only treatment for fatty liver disease. At Yale Medicine, we offer effective nonsurgical weight loss interventions in one place. We also conduct research to shed light on the underlying causes of fatty liver disease in order to develop improved treatments. If weight-loss surgery is required, Yale Medicine also has bariatric surgeons who are available to help with the latest, most proven techniques.