Fatty Liver Disease Explained: What Is It, How Is It Treated, and How Can a Dietitian Help?

Updated: June 2026 Author: Lisa Spriet, Registered Dietitian

Being told you have a fatty liver can feel confusing! Are you unsure what your next steps should be? Can changing the way you eat help? Overwhelmed by all the acronyms you’ve come across? Well, fear not, because we understand what you’re going through and are here to help explain! This blog will take you through the basics of fatty liver, including updated terminology, current lab values, and the latest research. We will also help you get started on reversing fatty liver. Let’s dive in!

What Is Fatty Liver?

The liver naturally has a small amount of fat in its cells, which is completely normal. But when too much fat is stored in the liver, it becomes a problem. You have fatty liver disease when more than 5% of your liver is made up of fat. Having this condition puts your liver at risk of more serious injury, including inflammation and scarring, which can eventually lead to liver failure.

What Do MASLD, MASH, and NAFLD Mean?

If you have recently seen your doctor and noticed different terms on your paperwork, you are not alone. In 2023, the medical community updated its naming system for fatty liver disease. The new names better reflect the root cause, metabolic health factors like blood sugar, weight, and cholesterol, rather than simply describing what fatty liver is not (i.e., not alcohol-related). You may still see the older terms used by some physicians, so knowing both is helpful.

Old Term: Non-Alcoholic Fatty Liver Disease (NAFLD)

New Term: Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)

What It Means: Fat build-up in the liver linked to metabolic risk factors

Old Term: Non-Alcoholic Steatohepatitis (NASH)

New Term: Metabolic Dysfunction-Associated Steatohepatitis (MASH)

What It Means: Liver inflammation on top of fat build-up

Old Term: Simple Fatty Liver

New Term:Metabolic Associated Steatotic Liver (MASL)

What It Means: Early Stage – fat without inflammation

MASLD is now the most common chronic liver disease worldwide, affecting approximately 38% of adults globally and roughly 1 in 4 Canadians. The liver is responsible for processing everything you eat and drink. Think of it like a waste removal plant attached to your body’s plumbing; fat accumulation is the equivalent of sludge building up in the pipes, interfering with normal function.

What Causes Fatty Liver Disease?

Unhealthy alcohol use is one cause of fatty liver, but MASLD specifically refers to fat accumulation driven by metabolic factors. The most common contributors include:

Dietary Habits

• Drinking sugar-sweetened beverages such as juice, soda, pop, and energy drinks regularly
• Eating too many refined carbohydrates, such as cookies, baked goods, sugary cereals, and white bread products
• High intake of fructose, found in sweetened foods and drinks
• Unbalanced eating habits, such as very large, infrequent meals

Body and Metabolic Factors

• Excess belly fat (visceral fat)
• Obesity
• Insulin resistance, pre-diabetes, or type 2 diabetes
• Metabolic syndrome (a cluster of high blood pressure, high cholesterol, high blood sugar, and a large waist circumference)
• Poor gut health
• High triglycerides in the blood

Many of these factors are interconnected. For example, daily refined carbohydrate intake can raise blood sugar levels, promote belly fat, and contribute to MASLD over time.

How Does Fatty Liver Disease Progress?

Without intervention, MASLD can progress through several stages:

MASLD / MASL — Fat in the liver, no inflammation. This stage is reversible with lifestyle changes.
MASH (formerly NASH) — Fat plus inflammation and liver cell damage. This can also improve with the right treatment.
Fibrosis — Scar tissue begins to build up, impairing blood flow through the liver. Partially reversible in early stages.
Cirrhosis — Extensive scarring that severely disrupts liver function. This stage is not reversible.
Liver Failure — At this point, the only treatment option is a liver transplant.

Early identification and treatment are critical. With proper lifestyle intervention, MASLD can be fully reversed to a healthy liver, and MASH can be reversed to MASLD. Fibrosis and cirrhosis, however, are permanent.

How Is Fatty Liver Disease Diagnosed?

There are currently three main ways to assess fatty liver disease:

Blood Tests

Liver enzyme tests are markers of inflammation and liver cell injury. The most commonly measured are alanine aminotransferase (ALT), aspartate aminotransferase (AST), and gamma glutamyl transferase (GGT). If cirrhosis is suspected, your doctor may also check bilirubin (to assess how your liver breaks down waste), albumin (a protein made by the liver; low levels suggest damage), and prothrombin time or INR (a measure of blood clotting).

Your doctor may also calculate a FIB-4 score using your age, ALT, AST, and platelet count. This is an estimate of liver fibrosis risk. Current guidelines recommend that patients with a FIB-4 score of 1.3 or higher be referred for further testing with a FibroScan.

FibroScan (Vibration-Controlled Transient Elastography)

FibroScan uses ultrasound waves to measure the stiffness of your liver, which reflects the degree of fibrosis (scarring). It is non-invasive, painless, and takes about 10 minutes. It provides two measures: the CAP score, which estimates the amount of fat in the liver, and the Liver Stiffness Measurement (LSM), which estimates the degree of scarring. Blood tests alone do not always accurately reflect fat accumulation or fibrosis, which is why FibroScan is an important diagnostic tool.

Current guidelines use LSM results to guide next steps:

• LSM below 8 kPa — Lower-risk MASLD; follow up with your family doctor
• LSM between 8 and 10 kPa — Borderline; a second test may be recommended
• LSM of 10 kPa or higher — Suggests moderate to advanced fibrosis; referral to a liver specialist is recommended

Liver Biopsy

A liver biopsy remains the gold standard for definitively diagnosing MASH and staging fibrosis. Given its invasive nature, it is typically reserved for cases where non-invasive tests are inconclusive.

What Is The Best Diet For Managing Fatty Liver Disease?

Diet is the single most powerful tool for reversing MASLD. The Mediterranean diet is the most well-researched and widely recommended eating pattern for fatty liver disease, and is endorsed by all major clinical practice guidelines. It has been shown to reduce liver fat, lower inflammation, and improve metabolic health — even without significant weight loss.

The Mediterranean diet emphasises:

• Plenty of whole vegetables and fruits
• Whole grains such as oats, barley, quinoa, and whole wheat
• Legumes such as lentils, chickpeas, and beans
• Fatty fish such as salmon, sardines, and mackerel (at least twice weekly)
• Healthy fats from extra virgin olive oil, avocado, nuts, and seeds
• Lean poultry, eggs, and plain low-fat dairy in moderation
• Limited red and processed meats
• No sugar-sweetened beverages

Beyond the overall dietary pattern, a few specific priorities stand out for liver health:

Reduce added sugars and fructose. Added sugars, and fructose in particular, are directly converted to fat in the liver. Cutting out sugar-sweetened beverages, sweetened cereals, candy, and packaged baked goods is one of the most impactful steps you can take.

Limit refined carbohydrates. Processed grains such as white bread, white rice, crackers, and pastries drive up blood sugar and insulin, promoting fat storage in the liver. Swapping these for whole grain versions makes a meaningful difference.

Increase fibre. Fibre from vegetables, fruits, legumes, and whole grains helps regulate blood sugar, feeds beneficial gut bacteria, and supports healthy liver function.

Prioritise omega-3 fats. Fatty fish, walnuts, ground flaxseed, and chia seeds provide anti-inflammatory omega-3 fatty acids that have been shown to help reduce liver fat.

Reduce saturated fat. Saturated fat from fatty meats, full-fat processed foods, and deep-fried items promotes liver inflammation and fat accumulation. Replacing these with unsaturated fats from olive oil, fish, and nuts is beneficial.

Choose water, tea, or black coffee. Staying well-hydrated with water and unsweetened beverages supports liver function. Research also suggests that drinking two or more cups of coffee per day may be associated with a lower risk of fibrosis progression in people with MASLD, likely due to anti-inflammatory compounds such as caffeine and chlorogenic acid.

Aim for modest weight loss if applicable. Losing 7 to 10% of body weight through a combination of healthy eating and physical activity is one of the most effective ways to reduce liver fat and improve liver health outcomes.

Be physically active. Aim for 30 to 60 minutes of moderate activity on most days of the week. Both aerobic exercise and resistance training have been shown to benefit liver health independently of weight loss.

Many of our clients who follow these recommendations consistently see complete resolution of fatty liver within 3 to 6 months, depending on severity.

What Are Common Myths About The Fatty Liver Diet?

There is a lot of misinformation online about what people with MASLD should and should not eat. Here are some of the most common myths, and what the evidence actually says.

Myth: You need to eliminate all carbohydrates.

This is one of the most widespread misconceptions. While reducing refined carbohydrates (white bread, sugary cereals, pastries) is important and well-supported by evidence, cutting out all carbohydrates is not necessary or recommended for most people with MASLD. In fact, the Mediterranean diet (the gold standard for fatty liver) includes plenty of carbohydrates in the form of whole grains, legumes, vegetables, and fruit. The quality and type of carbohydrate matters far more than simply eliminating the entire food group.

Myth: You cannot eat fruit because it contains fructose.

Fruit is frequently avoided by people with fatty liver because of its natural sugar content, but this is not supported by the research. The fructose that drives liver fat accumulation comes overwhelmingly from added fructose in sweetened beverages, packaged foods, and processed snacks, not from whole fruit. Whole fruit is actually recommended as part of a liver-healthy diet because it provides fibre, antioxidants, vitamins, and polyphenols that support liver health. Fruit juice, on the other hand, lacks fibre and delivers a concentrated dose of sugar, so it is best limited.

Myth: Only calories matter, not food quality.

The composition of your diet matters independently of calorie intake. Research consistently shows that the types of foods you eat, not just total energy, directly influence liver fat accumulation, insulin sensitivity, and inflammation. Replacing refined grains and added sugars with whole foods has measurable benefits for liver health regardless of whether overall calorie intake changes.

Myth: Fatty liver means you need to follow a fat-free diet.

Healthy fats are actually an important part of a liver-friendly diet. Unsaturated fats from olive oil, avocado, fatty fish, nuts, and seeds help reduce liver inflammation. It is saturated fats (from fatty meats, processed foods, and fried foods) and trans fats that worsen MASLD and should be minimised.

Myth: A very strict or extreme diet is needed to see results.

Sustainable, moderate changes are more effective in the long run than severe dietary restriction. Even a Mediterranean-style eating pattern followed consistently (without being perfect) produces significant improvements in liver fat and metabolic markers.

What Dietary Supplements Help With Fatty Liver Disease?

While there is no supplement that replaces a healthy diet and lifestyle, some nutraceuticals have shown promising results in supporting liver health in people with MASLD. It is important to speak with a registered dietitian or your physician before starting any supplement, as not all are appropriate for everyone.

Omega-3 Fatty Acids: (Fish Oil) Omega-3 supplementation, specifically EPA and DHA from fish oil, has been one of the most studied nutraceuticals for MASLD. Research suggests it may help reduce liver fat and support the immune system’s anti-inflammatory response. Results are mixed when it comes to fibrosis, so omega-3s are most useful as part of a broader dietary strategy rather than as a standalone treatment.

Vitamin E: Vitamin E is an antioxidant that has been shown in some studies to reduce liver fat and inflammation in non-diabetic adults with MASH. It is one of the more evidence-backed supplements in this area. However, it is not recommended for everyone — in particular, it is generally not advised for people with type 2 diabetes or advanced liver scarring. High-dose vitamin E supplementation should only be taken under the guidance of a healthcare professional.

Silymarin (Milk Thistle): Silymarin, the active compound in milk thistle, is a well-known herbal supplement with antioxidant and anti-inflammatory properties. Some studies suggest it may help reduce liver enzymes and support liver cell protection in people with MASLD. Evidence is promising but still emerging, and it is considered a reasonable complementary option when used alongside dietary changes. Silymarin is contraindicated with several medications, so consult your doctor or dietitian before trying it.

Probiotics: There is a strong connection between gut health and liver health, often called the gut-liver axis. Imbalances in gut bacteria (dysbiosis) are commonly seen in people with MASLD. Probiotic supplementation has been studied for its ability to reduce liver fat, lower liver enzymes, and improve metabolic markers. Certain strains appear beneficial, though the research is still evolving, and for this reason we often recommend a probiotic blend, versus single strain. A registered dietitian can help guide you on whether a probiotic may be appropriate for your situation.

Berberine: Berberine is a plant-derived compound that has shown positive effects on blood sugar regulation, insulin sensitivity, and liver fat in people with MASLD. Emerging research is encouraging, though it is not yet considered a first-line recommendation. It may be a useful complementary option, particularly for those with elevated blood sugars.

A Note on Supplements: Supplements can support liver health as part of a comprehensive plan, but they are not a shortcut. The foundation of fatty liver reversal is always diet, physical activity, and metabolic health management. Your registered dietitian can assess whether specific supplements are appropriate for you based on your individual health profile, lab values, and medications.

Are There New Medications For Fatty Liver Disease?

For many years, lifestyle changes were the only treatment for MASLD and MASH. That changed in 2024 with the FDA approval of resmetirom (Rezdiffra), the first medication specifically approved to treat MASH in adults with moderate to advanced fibrosis. In 2025, semaglutide (a GLP-1 receptor agonist already used for diabetes and weight management) also received FDA approval for noncirrhotic MASH with moderate to advanced fibrosis. Both medications are prescribed by physicians and work best alongside lifestyle changes. They are not currently widely available in Canada, but this is an evolving area. Speak with your physician if you believe you may be a candidate.

How Can A Registered Dietitian Help With Fatty Liver Disease?

With liver disease, there is a lot to manage: your diet, blood lab values, goals, medications, fitness, and many other health factors. A Registered Dietitian can support you by:

Personalised Dietary Counselling

– Building a meal plan tailored to your specific health needs, preferences, and lifestyle, including what to eat, what to limit, and practical strategies for grocery shopping, label reading, and eating out
– Guiding appropriate, sustainable weight loss when indicated
– Assessing whether specific supplements are appropriate for your situation
– Helping you set realistic goals and overcome barriers to change

Navigating the Process

– Interpreting your lab values (ALT, AST, FIB-4, and more) and explaining what they mean for your health
– Staying current on the latest MASLD guidelines and research so your plan reflects best practices
– Providing ongoing support and accountability throughout your journey

By following these recommendations consistently, many clients see complete resolution of fatty liver within 3 to 6 months, depending on severity.

You can download a program overview on our Liver Health page, or take a self-paced course to learn more about reversing fatty liver through nutrition.

Key Terminology Summary

Term: MASLD
What It Means: Metabolic Dysfunction-Associated Steatotic Liver Disease — the new name for NAFLD

Term: MASH
What It Means: Metabolic Dysfunction-Associated Steatohepatitis — the new name for NASH (inflammation stage)

Term: MASL
What It Means: Simple fat in the liver without inflammation

Term: Fibrosis
What It Means: Build-up of scar tissue in the liver

Term: Cirrhosis
What It Means:  Advanced, permanent scarring of the liver

Term: FIB-4
What It Means:  A blood-based score used to estimate fibrosis risk

Term: FibroScan / VCTE
What It Means:  Non-invasive ultrasound test to measure liver stiffness and fat

Term: LSM
What It Means:  Liver Stiffness Measurement — result from FibroScan

Term: Resmetirom
What It Means:  First FDA-approved drug for MASH (approved March 2024)

Term: Semaglutide
What It Means:  GLP-1 receptor agonist; also FDA-approved for MASH (2025)

Author: Lisa Spriet, MSc, RD
Lisa Spriet is a Registered Dietitian and Co-Owner of NutriProCan, a national company of dietitians dedicated to improving health through nutrition. With over 20 years of experience in fitness, health, and wellness, she combines clinical expertise with entrepreneurial leadership. Lisa holds a Master of Science in Foods & Nutrition, has taught nutrition at Brescia University College (now Western University), and is a sought-after speaker at corporate wellness and health industry events. Lisa is known for creating innovative nutrition programs and leading a team of dietitians across Canada.