What is fatty liver disease?
Fatty liver disease, also known as hepatic steatosis, is a condition where excess fat builds up in the liver. It’s normal to have some fat in your liver, but if more than 5-10% of the liver’s weight is fat, then it is considered a fatty liver (1).
The two main types of fatty liver disease are:
- Non-alcoholic fatty liver disease (NAFLD)
- Alcoholic liver disease (ALD)
As the names suggest, NAFLD occurs in people who drink little to no alcohol, while ALD develops due to excessive alcohol intake. Other causes of fatty liver include malnutrition, certain medications, and metabolic disorders like diabetes.
NAFLD is incredibly common, affecting up to 25% of the global population (2). Its prevalence continues to rise in tandem with conditions like obesity, insulin resistance, and type 2 diabetes.
Left untreated, NAFLD can progress through the following stages:
- Simple fatty liver – Fat buildup without inflammation or liver damage.
- Non-alcoholic steatohepatitis (NASH) – Fat buildup with inflammation that can scar the liver.
- Advanced fibrosis – Extensive scarring in the liver.
- Cirrhosis – Severe irreversible scarring that can lead to liver failure.
Not everyone with NAFLD experiences progression through these stages. Simple fatty liver is generally benign, while NASH, fibrosis, and cirrhosis can seriously damage the liver.
What causes fatty liver disease?
Fat accumulation in the liver occurs when:
- There is increased delivery of fat to the liver.
- The liver produces excessive fat.
- The liver has a decreased ability to export or burn off fat.
In NAFLD, insulin resistance and metabolic problems disrupt normal fat processing in the liver:
- Insulin resistance promotes fat release from adipose tissue, flooding the liver with fat.
- The liver ramps up fat production in response to high insulin.
- Impaired fat export and oxidation leads to further accumulation.
Other factors like diet, gut microbiome, genetics, and oxidative stress further drive NAFLD development (3).
Meanwhile, excessive alcohol intake directly causes ALD by:
- Boosting fat synthesis in the liver.
- Promoting inflammation that damages liver cells.
- Generating harmful oxidative byproducts.
Removing the alcohol exposure can allow the liver to recover over time. However, prolonged, heavy drinking often leads to permanent scarring (cirrhosis).
How is fatty liver disease diagnosed?
Fatty liver is often first suspected based on blood tests showing elevated liver enzymes. However, liver enzymes can be normal even with significant fat buildup.
To confirm a diagnosis, imaging tests like ultrasound or MRI are used to visualize fat in the liver. A liver biopsy may be done to assess inflammation and scarring.
Once fatty liver is found, additional testing helps determine the cause. This includes:
- Medication and alcohol use history.
- Tests for metabolic disease like diabetes.
- Assessment of liver scarring via biopsy or imaging.
- Testing for viral hepatitis and autoimmune conditions.
What are the symptoms of fatty liver disease?
Early stage fatty liver usually causes no symptoms. As it progresses, possible symptoms include:
- Fatigue and weakness
- Loss of appetite and weight loss
- Abdominal pain
- Nausea and vomiting
- Confusion and impaired brain function
- Swelling in legs and abdomen
- Jaundice (yellow skin and eyes)
Once cirrhosis develops, severe complications can arise like liver failure, bleeding veins in the esophagus, buildup of abdominal fluid, and liver cancer.
Can fasting help treat fatty liver disease?
There is emerging evidence that fasting regimens may benefit patients with fatty liver disease.
How fasting impacts fatty liver
Animal and human studies show fasting elicits several liver changes that may alleviate fatty liver (4, 5):
- Fat breakdown – Fasting stimulates fat burning pathways and reduces fat storage-promoting enzymes.
- Insulin sensitivity – Fasting periods increase insulin sensitivity, which helps address insulin resistance.
- Inflammation – Fasting reduces pro-inflammatory cytokines and immune cell infiltration.
- Oxidative stress – Fasting induces endogenous antioxidant systems.
- Autophagy – Fasting clears damaged cell components via recycling processes.
- Necroinflammation – Fasting blocks cell death pathways that drive inflammation.
Through these mechanisms, fasting regimens can potentially resolve the core lipid accumulation, inflammation, and cell damage that drive fatty liver disease.
Types of fasting for fatty liver
Here are some fasting protocols that have shown promise for treating fatty liver disease:
This involves alternating between fasting and feeding periods on a regular schedule, like fasting for 16 hours every day or 24 hours 1-2 days per week.
In human studies, daily 16-20 hour fasts for 3-7 months markedly reduced fatty liver severity, with significant improvements in liver enzymes, liver fat content, oxidative stress markers, and insulin resistance parameters (6, 7).
Alternate day fasting
This fasting style alternates “fast days” where calorie intake is restricted to 25-35% of normal needs, with alternating “feed days” without food limitation.
Studies in both animals and humans show alternate day fasting decreases liver fat content, inflammation, and fibrosis markers in NAFLD, while improving insulin sensitivity and oxidative status (8, 9).
Periodic fasting (5:2 diet)
The 5:2 diet involves major calorie restriction (~75% reduction) for 2 non-consecutive “fast days” per week, and normal eating the remaining 5 days.
In overweight adults with NAFLD, the 5:2 diet over 8 weeks decreased liver fat content and visceral fat mass more than daily calorie restriction. Hepatic inflammation also declined (10).
Prolonged fasting (1-3 days)
This involves water-only or very low calorie fasting for an extended duration, typically 24-72 hours at a time.
Case studies in patients with NASH report 1-3 days of fasting every 2 weeks over 3-12 months markedly improved liver enzymes, steatosis, inflammation, and fibrosis. Some patients had reversal of advanced fibrosis (11, 12).
This fasting style limits daily eating to set hours, like an 8-10 hour eating window with 14-16 hours of fasting in between.
Among patients with NAFLD, 4 months of a 9-hour daily feeding window reduced liver fat, improved insulin resistance, and lowered oxidative stress versus no fasting (13).
Other tips for fatty liver treatment with fasting
To maximize the benefits of fasting for fatty liver disease, here are some additional tips:
- Focus on low-sugar, higher fat and protein foods during non-fasting periods.
- Minimize processed carbs, sweeteners, refined oils, and trans fats.
- Engage in light exercise like walking during fasts.
- Stay well hydrated with water, herbal tea, broths.
- Take electrolytes like magnesium, potassium, and sodium.
- Avoid alcohol consumption, which worsens fatty liver.
Those with liver disease should only fast under medical supervision. Some patients, like those with cirrhosis, may be advised against fasting regimens.
What foods help reverse fatty liver?
Dietary changes along with fasting can further help resolve fatty liver disease. Some of the top foods to incorporate include:
Fish like salmon, sardines, mackerel, and tuna provide omega-3 fats that reduce liver fat, inflammation, insulin resistance, and oxidative stress (14). Aim for 2 or more servings per week.
Nuts and seeds
Almonds, walnuts, chia and flax seeds provide plant-based protein, fiber, and monounsaturated fats that improve insulin sensitivity and decrease liver inflammation (15).
Rich in monounsaturated fats, olive oil enhances insulin sensitivity and protects the liver from oxidative damage (16).
Berries are packed with antioxidants like anthocyanins that can reduce inflammation, liver enzymes, and fibrosis risk (17).
Coffee boasts antioxidants that decrease liver enzyme levels. Opt for 2-3 cups daily (18).
Green tea antioxidants improve insulin sensitivity and inhibit liver fat accumulation (19). Drink 2-3 cups per day.
|Food||Liver Health Benefits|
|Fatty fish||Omega-3 fats reduce liver fat, inflammation & oxidative stress|
|Nuts & seeds||Plant protein, fiber & MUFAs improve insulin sensitivity & decrease inflammation|
|Olive oil||MUFAs enhance insulin sensitivity & protect from oxidative damage|
|Berries||Rich antioxidants reduce inflammation, liver enzymes & fibrosis|
|Coffee||Antioxidants lower liver enzymes|
|Green tea||Antioxidants improve insulin sensitivity & inhibit liver fat|
Avoid foods that worsen fatty liver
It’s also crucial to limit or avoid foods shown to exacerbate fatty liver disease like:
- Sugar sweetened beverages – Promote fatty liver and insulin resistance (20).
- Refined grains – Drive inflammation, oxidative stress, and NAFLD (21).
- Processed meats – Associated with worse fibrosis in NAFLD (22).
- Fried foods – Worsen inflammation and oxidative stress.
- Alcohol – Directly causes fat accumulation and liver damage.
Lifestyle changes that improve fatty liver
Aside from fasting and diet, other lifestyle measures can further help resolve fatty liver disease:
All types of physical activity improve insulin sensitivity, reduce liver fat and inflammation, and decrease fibrosis risk (23). Aim for 150-300 minutes per week.
As little as 3-5% weight loss can significantly improve NAFLD, with more lost further reducing liver inflammation and fibrosis (24).
Quitting smoking appears crucial for NAFLD treatment, as it drives progression to NASH and worsens fibrosis (25).
Managing psychological stress may decrease systemic inflammation that contributes to NAFLD (26). Try meditation, yoga, counseling, or support groups.
Poor sleep exacerbates insulin resistance and inflammation in NAFLD. Get 7-9 hours nightly (27).
Early research indicates fasting can improve key aspects of fatty liver disease, including resolving liver fat accumulation, reducing inflammation, optimizing insulin sensitivity, decreasing oxidative stress, and potentially reversing fibrosis.
Both animal studies and human clinical trials reveal promising results for various fasting regimens, from daily time-restricted feeding to prolonged multi-day fasts. Furthermore, fasting for fatty liver disease appears safe and effective when done under medical guidance.
For optimal treatment, fasting can be combined with dietary measures like increasing intake of fatty fish, nuts/seeds, olive oil, and antioxidant-rich foods while limiting sugar, refined grains, processed meats, and alcohol.
Other beneficial lifestyle changes include exercise, weight loss, stress management, quality sleep, and smoking cessation.
With a comprehensive lifestyle approach including fasting, individuals with fatty liver disease may successfully decrease fat buildup, heal inflammation, and prevent progression to advanced liver damage.