Among his fellow cops, Bob Eddis was always known as the Energizer Bunny. But in 2011, the ebullient former Philadelphia officer was sagging.

His diabetes doctors at Thomas Jefferson University Hospital sent him to see a liver specialist. After some additional tests, the former Fraternal Order of Police president got a shock: He had nonalcoholic fatty liver disease that had progressed to cirrhosis of the liver.

The news hit Eddis, now 62, hard.

"I was distraught," he said. "And surprised. I always associated liver problems with drinking, and I was never a drinker. Since I was diagnosed with diabetes in 2009, I haven't had a single drink. And before that I had two Seven and Sevens a year - one on my birthday and one on New Year's Eve."

Nonalcoholic fatty liver disease, in which at least 5 percent of liver cells show evidence of fat, has doubled over the last two decades with the rise of diabetes.

The problem has been most evident among those with type 2 diabetes, with up to 70 percent of patients estimated to have fatty liver.

About 20 percent of this group will go on to develop the more serious nonalcoholic steatohepatitis (NASH), which causes inflammation and damages the liver cells. Even more serious, about 3 percent progress to the point where fat causes scarring that can lead to cancer of the liver, cirrhosis, and the eventual shutdown of liver functions.

While fatty liver is in itself a benign condition, there is no test to predict whether fatty liver will lead to NASH or cirrhosis.

"By 2020, NASH will be the number-one reason for liver transplants," said Dina Halegoua-De Marzio, director of the Fatty Liver Center at Thomas Jefferson University Hospital. "Even with a transplant, there is no guarantee that NASH can't return."

When you think of diabetes, you probably think of insulin and sugar.

But type 1 and type 2 diabetes can affect fat metabolism in very different ways. In type 1, where there is no insulin, the liver can burn through fat, resulting in a damaging condition called diabetic ketoacidosis. In people with type 2 diabetes, in which the body cannot use the insulin it produces, insulin resistance can cause fatty acid molecules in the blood to increase. Fat that can't be taken up by the muscles or organs of the body can get stored in the liver, a condition that can lead to fatty liver disease.

Obese people who produce too much insulin are also at risk for fatty liver.

While doctors understand the link between insulin resistance and fatty liver disease, other parts of the condition remain puzzling.

Once thought to be found only in patients with uncontrolled sugars, doctors are discovering that diabetic patients with well-controlled diabetes can also have fatty livers. And while obesity can also be a cause, "some populations, such as Asians, may have the condition without being over normal weight," said Mitchell Lazar, chief of the division of endocrinology, diabetes, and metabolism at Penn Medicine.

Fatty liver can also prove a problem for the millions of people diagnosed with "prediabetes."

"Early in the development of insulin resistance, when the pancreas can make enough insulin and blood sugar is normal, the pancreas keeps pumping out insulin," said Lazar. "Eventually the pancreas is not going to be able to keep up with the insulin resistance and will pump out less insulin. But people with prediabetes are pumping out more insulin than average, which can lead to fatty liver disease."

Another issue is that there are often no clear symptoms of fatty liver until it has become cirrhosis. There may be vague symptoms such as Eddis' fatigue, or a dull pain in the upper-right quadrant from an enlarged liver, "but usually it's discovered by coincidence," says Halegoua-De Marzio.

At present, there are no drugs to treat the condition. Vitamin E is sometimes recommended, but doctors mostly fall back on urging patients to improve their diets, lose weight, and increase their exercise. If patients can stick to this regimen, the condition can sometimes be reversed.

Drug companies have about 10 medications in clinical trials, some in advanced trials, that have shown a lot of promise, said Halegoua-De Marzio.

Medications are focused on reducing the fat in the liver and helping with scarring to prevent progression to cirrhosis.

There are no current FDA recommendations to regularly screen people with type 2 diabetes for fatty liver. Doctors don't have a test to indicate "who is going to progress from fatty liver to cirrhosis, there are no specific drugs to treat fatty liver, and we don't know if treatment will lead to improvement in the long run," said Lazar. He notes that tests to check for liver disease, including MRIs, biopsies, and ultrasounds, can be costly.

"Because we don't have any therapies to make it better, we're not doing screening," he said. "It's a bit of the chicken and the egg."

Eddis visits the liver specialist every six months to get a scan that sends pulsations through the liver to see whether his cirrhosis has gotten worse. So far, he has avoided a transplant and is working with a nutritionist to lose weight and bring down his sugars.

"I was really upset when they told me I had cirrhosis," he said. But taking better care of himself seems to be paying off. In his retirement, he has a part-time job and his Type A energy seems to have returned. "I'm actually feeling pretty good, to tell you the truth."

Risk Factors

Some health issues that can increase your risk of developing nonalcoholic fatty liver disease include:

Gastric bypass surgery
High cholesterol and/or triglycerides
Metabolic syndrome
Polycystic ovary syndrome
Sleep apnea
Type 2 diabetes
Underactive thyroid (hypothyroidism)
Underactive pituitary gland (hypopituitarism)