What you eat can affect your liver’s ability to function, and over time, can even lead to permanent damage or disease. Here are three habits that harm your liver—and one that can help it.

Your liver is the multi-tasking marvel of the human body, toiling away every day to digest fats, recycle blood cells, store energy for future use, and filter the blood coming from the digestive tract, protecting you from a wide variety of dangerous toxins. But people don't often think about their livers or realize that what they eat can affect its ability to function—sometimes permanently. In fact, certain types of food can contribute to liver disease, scarring, or even liver failure if eaten too often. Here are three eating habits that could take a toll on your liver—and one that can help it.

Your diet is heavy on unhealthy fats, sugar, and animal protein

Up to 25% of all people in the U.S. are thought to have non-alcoholic fatty liver disease or NAFLD, according to the American Liver Foundation. In NAFLD, excess fat infiltrates the liver, affecting its ability to function. The earliest stage, called fatty liver (that's when 5% to 10% of the liver's weight is fat), often has no symptoms. In general, NAFLD is more common in people who are overweight, obese, or have type 2 diabetes, and cases have has risen in tandem with the obesity epidemic. NAFLD is the most common cause of chronic liver disease in the United States, says Kristen Roberts, PhD, RD, an assistant clinical professor of Internal Medicine at The Ohio State University Wexner Medical Center in Columbus, Ohio.

One study found that overweight people who consume a lot of animal protein are at higher risk of fatty liver than those who do not. And other research suggests a diet heavy on unhealthy fats can lead to NALD. So munching on foods high in trans fat and saturated fat—like potato chips and other packaged products—may be a factor.

But, Roberts notes that not all fats are harmful to your liver. “Achieving weight loss from a low-calorie diet versus a low-fat diet is still under debate, but overconsumption of calories that leads to being overweight or obese increases your risk of developing liver disease,” she says. The link between liver disease and specific foods is not well understood (other research has suggested fast food; fructose-laden sugary drinks; a lack of vitamin E, vitamin D, and healthy fats; or other factors may also play a role) but research suggests insulin resistance and an increase in fatty acids (from a fat- and sugar-laden diet) contribute to inflammation and irreversible scarring of the liver.

“For anybody that is overweight or obese, our main goal is to reduce body weight,” Roberts says. She says teaching patients to eat good fats (think nuts, fish, and olive oil), fruits, vegetables, and healthy carbohydrates in proper proportions is the key to preventing and reversing liver issues. “It’s important to look at overall caloric intake.”

Credit: Photo: Greg Dupree

You drink too much alcohol

This may be the most obvious and well-known liver-damaging move. Typically, the liver processes one standard drink (10 to 15 grams of alcohol) in an hour’s time. But if you consume more than this, and do it often enough, over time, your liver is at risk for developing fat deposits, similar to NAFLD. This condition, known as alcoholic fatty liver disease, happens when fat is stored in liver cells that cannot be metabolized. This may not cause obvious symptoms; only a doctor can detect it through an exam, blood tests, or a biopsy.

According to Roberts, consuming alcohol can speed up the progression of pre-existing liver disease because it increases the accumulation of fatty acids in the liver. “Depending on the type and severity of liver disease, your doctor may recommend consumption in moderation.” Following the U.S. Dietary Guidelines for Americans is a good rule of thumb: a maximum of two drinks per day for men and one drink per day for women.

However, if you already have liver damage related to alcohol intake, Roberts says it’s often recommended to avoid drinking completely. “One function of our liver is to metabolize alcohol, so if you have liver damage and continue to drink, it’s kind of a snowball effect,” she says. Your liver won’t metabolize alcohol as effectively with damage and chronic alcohol consumption can lead to even more liver damage..

If excessive drinking continues, fatty liver disease can progress into alcoholic hepatitis, which is characterized by inflammation and mild scarring. And if drinking continues, you can develop alcoholic cirrhosis, an irreversible scarring of the liver’s tissue. According to the American Liver Foundation, many heavy drinkers have alcoholic fatty liver disease (and just about everyone who has more than 6 drinks a day will have it), about 35% have alcoholic hepatitis, and 10-20% have cirrhosis. However, it may be possible to reverse alcoholic fatty liver disease if you lay off of the alcohol before the damage is too advanced.

You load up the salt

Experts generally recommend consuming no more than 2,000-2,400 milligrams of salt daily. Chances are you’re consuming much more than that, though. “Americans consume a lot of sodium,” says Roberts. “We tend to have 5,000, 6,000, or even up to 10,000 milligrams a day due to fast foods and packaged foods that use salt as a preservative.”

For people who have pre-existing liver problems, excess sodium can cause water retention and inflammation in the abdomen. Both of these can overwork the liver.

Roberts says following a low sodium diet can be challenging, but for patients with scarring of the liver or cirrhosis, it’s essential. “A low-sodium diet can prevent several complications from the fluid building up in the body,” she says.

You drink coffee

Java lovers rejoice: This is one daily habit that's good for your liver. In a 2014 review, researchers found that people at risk for liver problems who drank coffee were less likely to have elevated liver enzymes, a sign of liver damage, than non-drinkers. What's more, coffee drinking was linked to a better response to treatment in people with hepatitis C, a lower risk of liver cancer, and slower progression to cirrhosis. "Therefore, in patients with chronic liver disease, daily coffee consumption should be encouraged," the researchers concluded. Or in other words, drink up!