by Cassie Story, RD, Nutrition Subject Matter Expert
If you have heard the term “fatty liver,” you may picture a condition caused by alcohol. But one of the most common forms of fatty liver disease is closely tied to metabolic health, including obesity, type 2 diabetes, high blood pressure and abnormal cholesterol levels.
Today, this condition is called metabolic dysfunction-associated steatotic liver disease, or MASLD. It was previously known as nonalcoholic fatty liver disease, or NAFLD. Its more advanced inflammatory form is called metabolic dysfunction-associated steatohepatitis, or MASH, which was previously called NASH. The terminology changed in 2023 to better reflect the metabolic drivers of the disease.
How Are Obesity and MASLD Connected?
Obesity is one of the strongest risk factors for MASLD, although it is not the only one.
A 2025 review found that the prevalence of MASLD is approximately 75% among people with obesity, compared with an estimated 38% in the overall global population.
A separate study of 539 adults with overweight or obesity found that 67.3% had MASLD when researchers used advanced MRI-based testing. About 11% had advanced liver fibrosis and 4.5% had cirrhosis.
Why is the connection so strong?
Obesity can contribute to insulin resistance and changes in how fat is stored and released throughout the body. Increased levels of fatty acids can reach the liver, where excess fat may accumulate. Over time, metabolic stress, inflammation and liver-cell injury can contribute to progression from MASLD to MASH and fibrosis.
Still, body weight alone does not determine who develops liver disease. Genetics, body-fat distribution, muscle mass and other metabolic factors also influence risk. MASLD can even occur in people whose BMI falls within the “normal” range.
Why MASH Matters
Many people with MASLD have few or no noticeable symptoms. That means liver disease can progress without someone realizing it.
Some people with MASLD develop MASH, where fat accumulation is accompanied by inflammation and liver-cell damage. Continued injury can lead to fibrosis or scarring. More advanced fibrosis can eventually progress to cirrhosis and increase the risk of liver cancer.
This is one reason screening and early identification matter, particularly for people who have several metabolic risk factors.
OAC provides additional education about obesity, MASH, screening and liver health. As well as, the Health Talk Liver Health and Obesity: Understanding the Connection with Jonathan Stine, MD, if you’re looking for more information.
What Can You Do About MASLD?
Treatment depends on how advanced the disease is and what other health conditions are present.
For many people, treatment includes addressing the underlying metabolic factors associated with MASLD. This may include nutrition, physical activity, treatment for obesity, diabetes management and management of blood pressure and cholesterol. Current research also supports the use of obesity medications and metabolic procedures in appropriately selected patients.
Start the Conversation
Because MASLD may not cause obvious symptoms, you may not know whether liver health should be part of your medical care.
If you live with obesity, type 2 diabetes or other metabolic risk factors, ask your healthcare provider whether you should be assessed for MASLD or liver fibrosis.
The Your Weight Matters Take the Challenge can help you prepare for a broader conversation about weight, health risks and treatment options.
Liver disease is another reminder that obesity can affect health in ways that are not always visible. Understanding that connection gives you one more piece of information to bring into your healthcare decisions.
References
Koliaki, Chrysi, et al. Metabolically Healthy Obesity and Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD): Navigating the Controversies in Disease Development and Progression. Current Obesity Reports. 2025;14(1):46.
Romanos, M., et al. Obesity and Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD): A Literature Review on Pathophysiology and Treatment. Diabetes, Obesity and Metabolism. 2026;28(Suppl. 2):19-30.
Yang, A. H., et al. Prevalence of Steatotic Liver Disease, Advanced Fibrosis and Cirrhosis Among Community-Dwelling Overweight and Obese Individuals in the USA. Gut. 2024;73(12):2045-2053.
