Fatty Liver Disease and Insulin Resistance: What to Know About MASLD

Fatty liver disease is common, quiet, and closely tied to the same metabolic problems we see in primary care every day. Many people learn they have it only when a routine lab or ultrasound shows something unexpected. If that is you, the finding is worth taking seriously, and it is also very workable.

What MASLD is and why the name changed

Fatty liver disease means extra fat builds up in liver cells. In 2023, major liver societies renamed the most common form from NAFLD to metabolic dysfunction-associated steatotic liver disease, or MASLD (Rinella et al., 2023). The new name points to the cause: the condition usually travels with excess weight, type 2 diabetes or prediabetes, high blood pressure, and abnormal cholesterol.

The same group uses MASH for the more active form, where fat comes with inflammation and liver cell injury. MASH can lead to scarring, called fibrosis, and over years to cirrhosis in a minority of people. Most people with MASLD never get that far, but we cannot tell who will without looking.

It is also common. A large meta-analysis estimated that roughly one in four adults worldwide has fatty liver disease (Younossi et al., 2016), and more recent estimates run higher.

How insulin resistance drives it

When your cells respond poorly to insulin, your body makes more of it. High insulin levels push the liver to make and store more fat, and fat tissue releases more fatty acids that end up in the liver. The result is a loop: liver fat worsens insulin resistance, and insulin resistance feeds more liver fat.

This is why we treat fatty liver as a metabolic condition, not a separate liver problem. If you want the full picture of how we find and treat the underlying issue, our post on insulin resistance covers it. Liver fat is also one of the clearer signs that insulin resistance has been present for a while.

How we check for it

MASLD rarely causes symptoms, so we look for it in people at higher risk. That includes anyone with type 2 diabetes, prediabetes, obesity, or several features of metabolic syndrome. The AASLD guidance recommends a stepwise approach (Rinella et al., 2023):

• Blood work. Liver enzymes (ALT and AST), platelets, A1C or fasting glucose, and a lipid panel. Liver enzymes can be normal even when fat is present, so a normal result does not rule it out.
• FIB-4 score. A simple calculation from your age, ALT, AST, and platelet count that estimates the chance of significant scarring.
• Elastography. If FIB-4 is not low, a noninvasive scan measures liver stiffness, which tracks with fibrosis.

A liver biopsy is rarely needed. We also check for other causes of liver enzyme changes, such as viral hepatitis, medications, and alcohol use, because several conditions can overlap.

What treatment looks like

The foundation is weight loss and lifestyle change, and the evidence for it is solid. In one study of people with biopsy-proven MASH, those who lost 10 percent or more of their body weight were much more likely to see the inflammation resolve, and many also saw scarring improve (Vilar-Gomez et al., 2015). Smaller losses helped less, but still moved liver fat in the right direction.

In practice, that means:

• A pattern of eating you can keep, with less ultra-processed food and sugary drinks and more fiber, protein, and unsaturated fats.
• Regular movement, including some resistance training. Exercise can lower liver fat even before the scale changes much.
• Limiting alcohol.
• Treating blood pressure, cholesterol, and blood sugar, since heart disease is a bigger threat than liver disease for most people with MASLD.

Medication enters the picture when lifestyle change is not enough or when fibrosis is present. Resmetirom, a liver-targeted thyroid hormone receptor agonist, improved MASH and fibrosis compared with placebo in a large phase 3 trial in people with moderate to advanced scarring (Harrison et al., 2024). Semaglutide, a GLP-1 medication, improved liver inflammation more than placebo in a phase 3 trial of MASH (Sanyal et al., 2025). Both have tradeoffs. Resmetirom is newer and can be costly or hard to access, and GLP-1 medications cause stomach side effects in many people and are often limited by coverage. We weigh these against your goals, your labs, and your other conditions.

What to expect from us

Telehealth works well for this condition. We review your labs and history by video, order the right tests, and coordinate any imaging or specialist referral you need. Follow-up is about trends: your weight, A1C, liver enzymes, and fibrosis risk over time. We also name what we do not know. Fibrosis can improve, but the evidence is stronger for slowing progression than for guaranteeing a cure.

Next steps

If you have diabetes, prediabetes, a larger waist, or a recent lab showing high liver enzymes, a simple screening can tell you where you stand. Visit our endocrinology care page to schedule a telehealth visit. Most major plans are accepted, including Medicare. Primary care should not be something you buy on top of the coverage you already pay for.