Weight loss is the cornerstone of treatment for fatty liver disease.Getty Images/iStockphoto
It’s the most common liver disease in Canada, affecting at least 25 per cent of adults. And its prevalence is rapidly rising.
According to a global study published by the Lancet on April 13, metabolic dysfunction-associated steatotic liver disease, or MASLD for short, is projected to affect 1.8 billion people worldwide by 2050, a 42 per cent increase from 2023.
Healthy lifestyle habits – especially diet and physical activity – are key to preventing and managing fatty liver disease.
When detected early, consistent lifestyle changes can improve and often reverse the condition.
Here’s what to know about fatty liver disease, plus evidence-based diet strategies that can help reduce fat buildup in the liver.
What is MASLD?
Previously known as non-alcoholic fatty liver disease, metabolic dysfunction-associated steatotic liver disease occurs when excess fat accumulates in liver cells. (Steatotic means fat buildup in an organ.)
This increase in liver fat is driven by metabolic risk factors rather than alcohol consumption.
Metabolic conditions such as obesity, elevated blood fats, high blood pressure, insulin resistance and Type 2 diabetes increase the risk of MASLD.
In most people, fat builds up in the liver primarily because of insulin resistance, which causes excess calories – especially from carbohydrates and fat – to be diverted to liver fat production rather than being burned or stored in adipose tissue.
MASLD may be detected when routine blood tests show elevated levels of liver enzymes, although high liver enzymes can be normal. The disease can also be discovered by abdominal ultrasound imaging.
In about 25 per cent of people with the disease, MASLD progresses to metabolic dysfunction-associated steatohepatitis, or MASH, which occurs when excess liver fat triggers inflammation, increasing the risk of continuing liver damage and serious complications over time.
Diet strategies for managing (and preventing) fatty liver disease
Lifestyle modification remains the first-line evidence-based approach for MASLD.
Weight loss – achieved through calorie restriction, physical activity and healthy eating – is the cornerstone of treatment.
Lose excess weight
Weight loss reduces liver fat accumulation and inflammation, and may improve liver fibrosis (scar tissue). It also improves insulin sensitivity.
Current guidelines in Canada, the U.S. and Europe consistently recommend a weight reduction of at least 5 per cent to reduce liver fat and 10 per cent or more to improve liver inflammation and fibrosis.
For people with MASLD who don’t carry excess body weight, a modest weight loss of 3 to 5 per cent may still be beneficial.
Follow a healthy diet pattern
Several dietary patterns have been studied for their effectiveness in managing MASLD.
Among them, the Mediterranean diet has shown the most consistent benefit for improving insulin resistance and reducing liver fat, even in the absence of weight loss.
This eating pattern highlights vegetables and fruit, whole grains, nuts, pulses and olive oil, while minimizing saturated fat, refined grains and added sugars.
Fibre, unsaturated fats, antioxidants and protective phytochemicals in the Mediterranean diet are thought to work together to improve insulin sensitivity and reduce liver fat and inflammation.
Emphasize unsaturated fats, limit saturated fats
Replacing saturated fats found in high-fat animal foods – such as butter, cream, cheese, fatty cuts of meat, processed red meat – with monounsaturated and polyunsaturated fats is consistently linked with less liver fat and a lower risk of MASLD.
Higher intakes of saturated fat are thought to worsen insulin resistance, increase liver fat production and promote inflammation. Diets richer in unsaturated fats, on the other hand, are linked to improved insulin sensitivity and better overall metabolic health.
Good sources of monounsaturated fats include olive oil, avocados, avocado oil, almonds, almond butter, peanuts, peanut butter, peanut oil and canola oil.
Foods that are rich in polyunsaturated fats include walnuts, sunflower seeds, chia seeds, ground flax, sunflower oil and grapeseed oil.
While unsaturated fats are generally more favourable to liver health than saturated fats, excess calories from any source can still promote liver fat accumulation.
Limit added sugars, avoid sugary drinks
An excess intake of added sugars – especially from sugar-sweetened beverages – is a strong contributor to the development of MASLD.
Consuming 250 millilitres of a sugary soft drink per day (less than a standard 355 ml can) has been tied to a significantly increased risk of developing MASLD. These drinks promote liver fat production and insulin resistance.
The World Health Organization advises limiting “free” sugars to less than 10 per cent of daily calories, with greater benefits below 5 per cent. For a 2,000 calorie diet, that’s equivalent to no more than 50 grams of free sugars per day and, ideally, no more than 25 g per day (about six teaspoons worth).
Free sugars include added sugars, as well as sugars naturally present in honey, maple syrup, agave syrup, pure fruit juice and fruit juice concentrates.
It’s best to avoid sugary drinks, including pure fruit juice.
Avoid alcoholic beverages
International guidelines advise avoiding alcohol as much as possible if you have MASLD. Even low levels of drinking can accelerate liver damage and increase the risk of liver cancer.
Complete abstinence is strongly recommended for people with advanced MASLD, such as steatohepatitis (MASH) or fibrosis.
Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan.
