Fatty liver disease (MASLD): Looking beyond the scale
8/24/2026 by Vijayvardhan Kamalumpundi, M.D., and Tiffany Wu, M.D., M.S.
The liver performs hundreds of essential functions, including regulating blood sugar, processing nutrients, filtering toxins and producing proteins needed for normal body function. When excess fat builds up in the liver, it can cause metabolic dysfunction-associated steatotic liver disease (MASLD), formerly called nonalcoholic fatty liver disease (NAFLD). MASLD now is the leading cause of chronic liver disease worldwide, surpassing alcohol-related liver disease and chronic viral hepatitis.
What is MASLD?
MASLD reflects underlying metabolic dysfunction and is closely linked to insulin resistance — a hallmark of prediabetes — obesity and conditions that increase the risk of heart disease, stroke and type 2 diabetes (metabolic syndrome). When the body becomes resistant to insulin, too much fat builds up in the liver.
Early disease often causes no symptoms, but ongoing metabolic stress can lead to liver inflammation, known as metabolic dysfunction-associated steatohepatitis (MASH), formerly known as nonalcoholic steatohepatitis (NASH). If left untreated, MASH can progress to scarring of the liver (cirrhosis), liver failure or liver cancer.
Why body weight doesn't tell the whole story
Although excess body weight is an important risk factor, body mass index (BMI) alone does not predict who develops MASLD. Fat surrounding internal organs (visceral fat) is strongly associated with insulin resistance and metabolic dysfunction.
As a result, some people develop MASLD despite having a normal BMI. Individuals of South Asian and East Asian ancestry are more likely to develop insulin resistance and accumulate visceral fat at lower BMI values than many other populations, increasing their risk for MASLD despite appearing thin.
The key takeaway is that metabolic health cannot be judged by body weight or appearance alone. BMI alone may underestimate metabolic risk in some populations. Consult with your healthcare team about screening for MASLD based on metabolic risk factors rather than body weight alone.
Who is at risk?
Your risk of MASLD is higher if you have these risk factors:
- Pre-diabetes or type 2 diabetes.
- Family history of type 2 diabetes.
- Having excess weight or obesity, particularly with increased fat around the waist — >40 inches in men or >35 inches in women*.
- High blood pressure.
- High cholesterol or high levels of triglycerides.
- South Asian or East Asian ancestry, particularly at lower BMI.
- An inactive lifestyle, with little or no movement or exercise.
*Waist circumference cutoffs may be lower for some Asian populations.
When to talk with your healthcare team
MASLD often causes no symptoms until liver disease has become more advanced. Many people learn they have the condition only after routine blood tests or imaging performed for another reason.
If you have risk factors for MASLD, talk with your primary care team about your liver health. Your care team may recommend blood tests to determine liver function and decide whether additional evaluation is needed, based on your individual risk factors. In some cases, this may include calculating a liver scarring risk score or obtaining specialized liver imaging.
Vijayvardhan Kamalumpundi, M.D., is a third-year Internal Medicine resident at Mayo Clinic in Rochester. Tiffany Wu, M.D., M.S., is a transplant hepatologist at Mayo Clinic in Rochester.