New research suggests otherwise, according to a Keck Medicine of USC study published today in Clinical Gastroenterology and Hepatology. 

Researchers discovered that people with metabolic dysfunction–associated steatotic liver disease (MASLD), the most common liver condition in the country affecting one-in-three adults, face significantly higher risk of liver fibrosis, or harmful scarring of the liver, if they engage in episodic heavy drinking. Episodic heavy drinking is four or more drinks in one day for women and five or more drinks in one day for men, at least once a month.  

Those who consume large amounts of alcohol in a single day at least once per month are three times more likely to develop advanced liver fibrosis than individuals who spread out the same total alcohol intake over time, according to the findings. 

Younger adults and men were more likely to report episodic heavy drinking, and the more drinks consumed at one time, the more liver fibrosis people tended to have. 

“This study is a huge wake-up call because traditionally, physicians have tended to look at the total amount of alcohol consumed, not how it is consumed, when determining the risk to the liver,” said Brian P. Lee, MD, MAS, a hepatologist and liver transplant specialist with Keck Medicine and principal investigator of the study. “Our research suggests that the public needs to be much more aware of the danger of occasional heavy drinking and should avoid it even if they drink moderately the rest of the time.”  

How the study was conducted 

Lee and his colleagues used data from the nationally representative National Health and Nutrition Examination Survey, a long-running health survey of the United States population. They included data from more than 8,000 adults, collected between 2017 and 2023. In particular, they looked at the link between episodic heavy drinking and advanced liver fibrosis to understand how drinking patterns — not just total drinks — may cause harm even to moderate drinkers, which is considered seven drinks a week for women and 14 or less for men.  

The research team focused on MASLD because of its prevalence among Americans. MASLD affects people with excess weight, obesity or other metabolic conditions, such as Type 2 diabetes, high blood pressure or high cholesterol, and is on the rise. Additionally, while MASLD is not defined as alcohol-related, Lee and his colleagues wanted to explore if alcohol did in fact play some role in the condition. 

More than one-half of the adults included in the study reported episodic heavy drinking and almost 16% of patients with MASLD were episodic heavy drinkers. 

The researchers compared people with MASLD with the same age, sex and average weekly alcohol consumption, segmenting some as episodic heavy drinkers and others as non-episodic heavy drinkers, to reach their conclusion that episodic heavy drinkers with MASLD had nearly three times higher odds of experiencing advanced liver fibrosis.  

Lee speculates that episodic heavy drinking can harm the liver both directly and indirectly. Drinking large amounts of alcohol at once can overwhelm the liver and increase inflammation, which leads to scarring and damage. People with MASLD may be particularly at risk, as Lee’s previous research has shown that obesity, high blood pressure and other conditions associated with MASLD can more than double liver disease risk. 

Alcohol-related liver disease has more than doubled in the last two decades, according to Lee. He believes this trend is driven by pandemic-era surges in drinking and an increase in people with risk factors for MASLD, like obesity and diabetes.  

“Although this study focused on patients with MASLD, these findings may also be pertinent to a broader patient population,” said Lee. “With more than half of adults reporting some episodic heavy drinking, this issue deserves further attention from both physicians and researchers to help better understand, prevent and treat liver disease.” 

“Alcohol-related liver disease is the main cause of liver-related death and these results are a major wakeup call to the dangers of drinking,” said Brian P. Lee, MD, MAS, a hepatologist and liver transplant specialist with Keck Medicine and lead author of the study.  

The study also sheds light on the demographics of American drinkers, uncovering that four groups make up a greater share of heavy drinkers than they did 20 years ago — women, adults 45 and older, those living in poverty and people with metabolic syndrome, a cluster of conditions that together raise the risk of coronary heart disease, diabetes and stroke. Previous studies have already associated these groups with a higher risk of liver disease when exposed to alcohol.  

“These findings — the first comprehensive look at the demographics of heavy drinking and their relation to liver disease since the 1990s — provide important new information about which population groups may need more intervention to curb alcohol use and may also explain the rise in liver disease over the years,” said Lee.  

Additionally, the study showed that the average drinking rate in America was unchanged over the last 20 years before the COVID-19 pandemic, suggesting that factors beyond alcohol quantity, such as changing health and demographic profiles, may be contributing to the rise in liver disease.  

“Our results show that the makeup of the American public with heavy alcohol consumption has changed compared to 20 years ago,” said Lee.  

Lee and his fellow researchers analyzed data from the National Health and Nutrition Examination Survey, which assesses the health and nutritional status of adults and children in the United States, from 1999-2020, the most recent year for which complete data was available.  

They tracked the total increase in significant liver disease — a stage of liver disease when the liver forms scar tissue that impairs liver function that is often caused by heavy drinking. The study examined the demographic and health profiles of adults 20 or older who drank heavily. According to the Centers for Disease Control and Prevention, heavy drinking is considered eight drinks per week for women and 15 for men. 

Lee believes that the study results will provide physicians with necessary updates to better treat patients and hopes they will lead to more screenings and interventions for high-risk populations.  

Jennifer Dodge, MPH, associate professor of research medicine and population and public health sciences with the Keck School of Medicine of USC, was also a study author.  

The study was supported by a grant from the National Institute on Alcohol Abuse and Alcoholism, grant number K23AA029752.  

These findings build on Lee’s previous work, including a February 2025 study that found heavy drinkers with diabetes, high blood pressure or increased waist size had double the risk of advanced liver disease, and a November 2024 study revealing that heavy drinking rose during the COVID-19 pandemic peak and continued for two years afterward. 

The answer may lie in three common underlying medical conditions, according to a new study published in Clinical Gastroenterology and Hepatology from Keck Medicine of USC. The research found that heavy drinkers with either diabetes, high blood pressure or a high waist circumference are as much as 2.4 times more likely to develop advanced liver disease.  

“The results identify a very high-risk segment of the population prone to liver disease and suggest that preexisting health issues may have a large impact on how alcohol affects the liver,” said Brian P. Lee, MD, MAS, a hepatologist and liver transplant specialist with Keck Medicine and principal investigator of the study. 

Diabetes, high blood pressure and a high waist circumference (35 inches for women; 40 inches for men), which is associated with obesity, belong to a cluster of five health conditions that influence an individual’s risk for heart attack and stroke known as cardiometabolic risk factors.  

Cardiometabolic risk factors have been linked to the buildup of fat in the liver (also known as metabolic dysfunction-associated steatotic liver disease), which can lead to fibrosis, or scarring of the liver. These risk factors affect more than one in three Americans, and cardiometabolic health has been worsening among the population, especially among those under 35, according to Lee.  

Alcohol also causes fat buildup in the liver, and alcohol consumption has been on the rise since the COVID-19 pandemic, said Lee. Due to the prevalence of both cardiometabolic risk factors and drinking in the United States, Lee and his fellow researchers undertook the study to investigate which cardiometabolic risk factors predisposed the liver to damage from alcohol. 

They analyzed data from the National Health and Nutrition Examination Survey, a large national survey of more than 40,000 participants, looking at the intersection of heavy drinking, individual cardiometabolic risk factors and the incidences of significant liver fibrosis. Significant liver fibrosis refers to liver scarring that can lead to liver failure.  

For the study, heavy drinking was characterized as 1.5 drinks a day for women (20 grams) and two drinks a day for men (30 grams). 

Researchers discovered that heavy drinkers with either diabetes or a high waist circumference were 2.4 times more likely to develop advanced liver disease and those with high blood pressure 1.8 times more likely. They found that the other two cardiometabolic risk factors — high triglycerides (elevated levels of a type of fat in the blood) and low HDL (high-density lipoprotein or “good” cholesterol) had less significant correlations to liver disease.  

While the study did not analyze why these three cardiometabolic risk factors are more dangerous for the liver, Lee speculates that these conditions share a common pathway to fat buildup in the liver that when combined with extra fat deposits in the liver from excessive alcohol, can cause significant damage.  

Lee emphasizes that the study does not imply it is safe for those without these three cardiometabolic risks to consume large amounts of alcohol. “We know that alcohol is toxic to the liver and all heavy drinkers are at risk for advanced liver disease,” he said.  

Lee hopes that the study results will encourage people to consider their individual health and risk profile when making decisions about alcohol consumption. He would also like to see practitioners offer more personalized health screenings and interventions for those who drink with cardiometabolic risk factors so that liver damage among this high-risk group can be caught early and treated.  

Norah Terrault, MD, a Keck Medicine gastroenterologist and division chief of gastroenterology and liver diseases at the Keck School of Medicine, was also a study author.  

What explains the different outcomes?  

The answer may lie in a condition known as metabolic syndrome, a cluster of conditions that together raise the risk of coronary heart disease, diabetes, stroke and other serious health problems. This syndrome, characterized by symptoms such as abdominal fat, high blood pressure, high cholesterol and high blood sugar, affects more than one in three Americans.  

A new study from Keck Medicine of USC published in the Annals of Internal Medicine shows that heavy alcohol use may be dramatically more damaging to the liver for people with metabolic syndrome.  

“Our research suggests that metabolic syndrome and alcohol interact in such a way that they multiply the effect of alcohol on the liver, more than doubling the risk of advanced liver disease among heavy drinkers,” said Brian P. Lee, MD, MAS, a hepatologist and liver transplant specialist with Keck Medicine who is the lead author on the study. “Drinking is harmful to the liver, but especially so for this segment of the population.”  

In the study, heavy alcohol use was defined as two drinks (a total of 12 fluid ounces) a day for women and three drinks (a total of 18 fluid ounces) per day for men.  

Lee and his colleagues were motivated to research a connection between advanced liver disease, alcohol use and metabolic syndrome after noticing that between 2009-2018, deaths from alcohol-associated liver disease surged in the United States by more than 30% while alcohol use, including heavy drinking, remained stable or declined.  

During the last 20 years, the number of Americans with metabolic syndrome increased significantly. Previous research has shown that metabolic syndrome can cause liver abnormalities.  

“We therefore hypothesized that metabolic syndrome could be an important contributor to this unexplained surge in advanced liver disease,” said Lee.  

For the study, Lee and his fellow researchers used data from the National Health and Nutrition Examination Survey, which assesses the health and nutritional status of adults and children in the United States, pulling together samples representing the U.S. population 20 years or older between 1999 and 2018. 

While the data revealed a slight increase in advanced liver disease with heavy alcohol use without metabolic syndrome, the greatest increase in advanced liver disease was found in those with combined heavy alcohol use and metabolic syndrome. 

Lee believes that the increased risk of liver damage from drinking is a result of an increase in the amount of fat in the liver. A healthy liver contains less than five percent fat; any more than that can lead to inflammation and cirrhosis (scarring) of the liver, liver cancer and liver failure.  

“Both metabolic syndrome and drinking increase liver fat, and we think that the combination of the two accelerates the accumulation of fat in the liver and fuels inflammation, resulting in a greater chance of liver disease,” said Lee.  

He hopes the study will encourage physicians who screen and diagnose patients with metabolic syndrome to also ask about alcohol use and look for liver disease.  

“Our study indicates that these conditions may often coexist, and it is in patients’ best interest to address both issues,” he said. “It’s also important for people with metabolic syndrome to realize they may be at an increased likelihood of advanced liver disease, and to monitor their drinking accordingly,” he added.  

The other authors of the study are Jennifer Dodge, MPH, assistant professor of research medicine and population and public health sciences with the Keck School of Medicine of USC;  Wendy Mack, PhD, professor of population and public health sciences with the Keck School of Medicine; Adam Leventhal, PhD, professor of population and public health sciences with the Keck School of Medicine and director of the USC Institute for Addiction Science and Norah Terrault, MD, MPH, a Keck Medicine gastroenterologist and division chief of gastroenterology and liver diseases with the Keck School of Medicine.