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Fatty Liver and Type 2 Diabetes: Why Liver Fat Is the Key to Remission

Most people with type 2 diabetes have excess liver fat. Former NIH scientist Dr. Sayantan Banerjee explains MASLD, how it raises glucose, how it's tested, and how to reduce it.

TYPE 2 DIABETES REMISSION

Dr. Sayantan Banerjee

10/31/20268 min read

If you have type 2 diabetes, there is a good chance you also have fat stored inside your liver. Many people only find out by accident, from a scan done for something else, or from a liver blood test that comes back slightly high. Often nobody explains what it means.

It matters a great deal. Fat in the liver is one of the main reasons blood sugar rises in type 2 diabetes. It is also one of the first things to improve when you lose weight, and that is a big part of why remission is possible. This article explains the link, the new names you may hear, how fatty liver is tested, and what reduces it.

The new name: MASLD

For years, the condition was called non-alcoholic fatty liver disease, or NAFLD. In 2023, international liver societies agreed new names, because the old one described what the condition wasn't, rather than what it was, and because many patients found the word "alcoholic" stigmatising.

The new term is metabolic dysfunction-associated steatotic liver disease, or MASLD. Steatotic simply means fatty. A more advanced, inflamed form is called metabolic dysfunction-associated steatohepatitis, or MASH, which used to be called NASH.

To be diagnosed with MASLD, you need excess liver fat plus at least one metabolic risk factor, such as type 2 diabetes or prediabetes, a large waist or raised BMI, high blood pressure, high triglycerides or low HDL cholesterol. Most people with type 2 diabetes meet that definition if they have a fatty liver.

You may still see the older terms in letters and reports. They refer to essentially the same group of people.

How common is it?

Very. Fatty liver is the most common liver condition in the US and the UK. Among people with type 2 diabetes, studies using scans have found that a large majority, often well over half, have excess liver fat. Rates are higher in people with obesity, and also high in people of South Asian and Hispanic heritage, even at lower body weights.

In most people it causes no symptoms at all, which is why it is so often missed.

Fatty liver when you aren't overweight

Fatty liver isn't only a problem for people with obesity. A significant minority of people with MASLD have a BMI in the normal range. This is sometimes called lean MASLD. It is more common in people of South Asian and East Asian heritage, and in people who carry most of their weight around the middle.

The explanation links back to the personal fat threshold. Some people have a limited capacity to store fat safely under the skin. Once that capacity is used up, even a modest gain in weight sends fat into the liver. A person can look slim and still have a liver full of fat.

This matters for diabetes, because people with lean MASLD can still develop type 2 diabetes. The good news is that they often need less weight loss to see improvement. In some studies of lean people with fatty liver, a loss of 3% to 5% of body weight was enough to make a real difference to liver fat.

If your BMI is normal but your waist is more than half your height, your triglycerides are high, or your liver tests are slightly raised, it is worth asking your doctor about your liver.

Signs your liver fat is falling

Most people won't have repeated liver scans, so how do you know if things are improving? A few signs help. Your fasting glucose falls, often before your HbA1c changes. Your waist measurement drops. Your triglyceride level on a blood test falls. If your ALT was raised, it often comes back towards normal. And many people say they feel less tired after meals. None of these is perfect, but together they give a good picture.

How liver fat raises blood sugar

To understand this, it helps to know what the liver does with glucose.

Between meals and overnight, your liver releases glucose into the blood to keep you supplied with fuel. After you eat, insulin rises and tells the liver to stop releasing glucose and start storing it instead.

When the liver is full of fat, it becomes resistant to insulin. It no longer responds properly to the signal to stop. So it keeps releasing glucose even when your blood sugar is already high. This is a major cause of high fasting glucose in type 2 diabetes, the reading you see first thing in the morning.

The fatty liver also exports more fat into the blood, in the form of triglyceride-rich particles. Some of that fat ends up in and around the pancreas, where it seems to impair the beta cells that make insulin. Professor Roy Taylor's group in Newcastle has called this the twin cycle: fat in the liver and fat in the pancreas, each making the other worse, and both driving glucose up.

Why this is good news for remission

Liver fat is surprisingly responsive. In Newcastle's MRI studies, liver fat fell sharply within the first week of a very low calorie diet, and fasting glucose came down at the same time. Over the following weeks, pancreatic fat fell, and the beta cells began to respond better.

That is the biology behind the DiRECT trial, in which 46% of people on a structured weight-loss programme were in remission at one year. It also explains why the first sign of improvement many people notice is lower morning glucose readings. The liver is releasing less glucose overnight.

You don't need a very low calorie diet to see this effect. Any approach that produces steady weight loss reduces liver fat. Studies suggest that losing around 5% of body weight noticeably reduces liver fat, while losing 7% to 10% or more improves inflammation and, in some people, early scarring.

Why it matters beyond diabetes

Most people with fatty liver never develop serious liver disease. But a minority develop inflammation (MASH), which can lead to scarring (fibrosis), and in some cases cirrhosis or liver cancer over many years. Type 2 diabetes is one of the strongest risk factors for this progression.

Fatty liver is also linked to heart disease. In fact, people with MASLD are more likely to die from cardiovascular disease than from liver disease. So reducing liver fat helps your heart as well as your glucose.

How fatty liver is tested

There isn't one perfect test. Doctors usually combine several.

Liver blood tests. Raised ALT or GGT can suggest a fatty liver, but many people with fatty liver have normal results. A normal liver blood test doesn't rule it out.

Ultrasound. A standard abdominal ultrasound can show a fatty liver, but it may miss milder cases and doesn't measure scarring.

Fibrosis risk scores. The FIB-4 score uses your age, liver enzymes and platelet count to estimate the risk of significant scarring. Many guidelines, including those used in the US and UK, recommend calculating FIB-4 in people with type 2 diabetes and fatty liver risk.

Elastography. If FIB-4 is not low, the next step is often a scan that measures liver stiffness, such as transient elastography (often called FibroScan), or an ELF blood test, which is widely used in the UK.

MRI. Specialist MRI can measure liver fat very precisely, but it is mainly used in research and specialist clinics.

If you have type 2 diabetes, it is reasonable to ask your doctor whether your liver has been assessed, and whether a FIB-4 score has been calculated.

What reduces liver fat

Weight loss. This is the most effective treatment. Steady weight loss of 5% to 10% of body weight makes a real difference, and more helps further.

Fewer sugary drinks and refined carbs. The liver turns excess fructose and refined carbohydrate into fat. Sugary drinks, including fruit juice in large amounts, are a particular problem. Cutting them is one of the simplest changes you can make.

A Mediterranean-style diet. Vegetables, legumes, whole grains, fish, olive oil and nuts, with less red and processed meat, have been shown to reduce liver fat even with modest weight change.

Exercise. Both aerobic exercise, such as brisk walking or cycling, and resistance training reduce liver fat, even without much weight loss. Around 150 minutes a week of moderate activity is a good target.

Less alcohol. Alcohol adds to liver fat and can speed up damage. If you have fatty liver, especially with signs of scarring, your doctor may advise cutting down a lot or stopping altogether. UK guidance is no more than 14 units a week for everyone, and less is better if you have liver disease.

Sleep. Poor and short sleep are linked to more liver fat and worse insulin resistance.

Coffee. Several observational studies link regular coffee drinking, without lots of sugar or syrup, to a lower risk of liver scarring. This isn't proof of cause, but for most people there is no reason to stop drinking coffee.

Medicines and liver fat

Some diabetes medicines also reduce liver fat. GLP-1 medicines such as semaglutide reduce liver fat, largely through weight loss, and have shown benefits for MASH in trials. Pioglitazone, an older diabetes tablet, also improves fatty liver in some people, though it can cause weight gain and fluid retention. SGLT2 inhibitors may reduce liver fat modestly.

In the US, a drug called resmetirom was approved in 2024 for adults with MASH and moderate to advanced scarring. It is a specialist treatment, not a substitute for weight loss.

Ask your doctor whether any of these are suitable for you. They work best alongside lifestyle change, not instead of it.

A simple plan to reduce liver fat

Ask for your liver tests and a FIB-4 score if you haven't had one.
Cut sugary drinks completely. Replace them with water, sparkling water, tea or coffee.
Aim to lose 5% to 10% of your body weight over the next six months.
Base meals on vegetables, protein and whole foods, with olive oil as your main fat.
Walk briskly for at least 30 minutes on five days a week, and add two sessions of strength exercise.
Keep alcohol well within the guidelines, or stop if advised.
Watch your fasting glucose. It is often the first number to improve as liver fat falls.
Recheck HbA1c and liver tests after three to six months.

Questions to ask your doctor about your liver

Have my liver blood tests been checked recently, and were any results raised?
Has a FIB-4 score been calculated for me?
Do I need a scan to check for liver scarring, such as a FibroScan or an ELF test?
Could any of my medicines affect my liver, or help reduce liver fat?
How much alcohol is safe for me, given my liver results?
When should my liver tests be repeated?

Writing down the answers, and the dates, makes it easier to see change over time.

How my book can help

The Type II Diabetes Remission Strategy explains the role of fat in the liver and pancreas in plain language, and why treating it means treating the cause rather than only the numbers. The 16-week programme combines everyday nutrition, strategic intermittent fasting, progressive exercise and daily habits. See the book page.

Frequently asked questions

Does fatty liver cause type 2 diabetes? It is one of the main drivers. Fat in the liver makes it resistant to insulin, so it releases too much glucose.

Can fatty liver be reversed? Yes, in most people. Weight loss of 5% to 10% significantly reduces liver fat.

How quickly does liver fat go down? On a very low calorie diet, liver fat can fall noticeably within a week. With slower weight loss, it falls over weeks to months.

Are normal liver blood tests reassuring? Not completely. Many people with fatty liver have normal liver enzymes.

What is a FIB-4 score? A calculation using age, liver enzymes and platelet count to estimate the risk of liver scarring.

Is fruit bad for fatty liver? Whole fruit in normal amounts is fine. Fruit juice and sugary drinks are the main problems.