Obesity is linked to a lot of issues that can impact your health and quality of life. One of these is a condition called fatty liver disease.
Fatty liver disease is an illness in which fat builds up in the liver. It happens because your liver can’t process and rid itself of fat efficiently.
There are two basic types of fatty liver disease: Alcoholic fatty liver disease happens when heavy drinking damages your liver and makes it less able to break down fat. The other more common type isn’t related to alcohol use. It was long called nonalcoholic fatty liver disease (NAFLD), because it’s found in people who drink little if any alcohol at all. Doctors and researchers now refer to it as metabolic dysfunction-associated steatotic liver disease (MASLD).
A number of things can increase your chances of getting MASLD. But having obesity may be the most common risk factor of all. In fact, up to two-thirds of people with MASLD have obesity.
Fat buildup can eventually damage your liver, prevent it from functioning properly, and may result in liver failure. Research also suggests there’s a strong link between MASLD and diseases of your heart and blood vessels. The encouraging news is that MASLD is treatable and can even be reversed. The key is catching the disease early and taking action.
Fatty Liver and Obesity: What’s the Link?
A top cause of obesity is consuming more calories than your body needs for energy. You store the extra calories as fat throughout your body, including in your liver.
As the rate of obesity has climbed in society, so have rates of MASLD. Currently, about one-third of adults globally have MASLD. Fatty liver in children – which used to be rare – has more than doubled since the late 1980s.
MASLD can range in severity. Doctors diagnose “simple fatty liver” (hepatic steatosis) when fat accounts for at least 5% of your liver’s overall weight. It usually doesn’t worsen or have symptoms and doesn’t affect your liver function. Most people with MASLD have simple fatty liver.
But about 20% of the time, MASLD becomes a more serious condition called metabolic dysfunction-associated steatohepatitis, or MASH (formerly known as nonalcoholic steatohepatitis, or NASH). This is when excess fat causes the liver to become inflamed. Chronic inflammation can scar the liver and lead to cirrhosis and eventually liver failure. MASH is actually the fastest-growing reason why people in the United States require liver transplants.
Symptoms of Metabolic Dysfunction-Associated Steatotic Liver Disease
Doctors tend to find evidence of MASLD when they are doing liver tests or imaging in the belly area (CT scans, ultrasounds) for patients who are at risk of MASLD or for some other medical reason. MASLD is called a silent disease because it generally causes few or no symptoms.
When people do have MASLD symptoms, they may feel:
- Fatigue
- Weakness
- Discomfort in the upper right belly area (where your liver is located)
MASH may also cause no symptoms. But this may change as the disease worsens and people get cirrhosis of the liver. Symptoms of MASH may include:
- Discomfort in the upper right belly area (where your liver is located)
- Poor appetite, nausea
- Severe tiredness and weakness
- Swelling in your hands, feet, and legs
- Unexplained weight loss
Do All People with Obesity Have Fatty Liver?
MASLD is not a given if you have obesity. But you certainly have a higher risk. Experts estimate that 75% of people who are overweight (with a body mass index of 25+) have MASLD. The rate climbs to 90% among people with class III obesity (a body mass index of 40+).
It’s not clear why some people with obesity get MASLD while others don’t. Experts aren’t sure, either, why MASLD remains stable and without symptoms in many cases, but advances to MASH in others.
Like with many other conditions and their risk factors, genes probably help tip the scales one way or another. In the case of MASLD, a family history of issues like diabetes or high cholesterol may heighten your risk of having the condition. So can being postmenopausal and of Asian or Hispanic descent. Having other health conditions like type 2 diabetes, insulin resistance, high cholesterol, and/or high blood pressure can raise your risk, too.
Can you have fatty liver without obesity?
Ten percent to 15% of people with MASLD are not obese or overweight and have a body mass index below 25.
Known as “lean MASLD,” this situation is most often seen in people of Asian descent. People with lean MASLD tend to fare worse than their overweight and obese counterparts. They are at higher risk of dying from diseases of the heart and blood vessels, and the condition progresses faster to advanced liver disease.
How Does Obesity Affect Fatty Liver Risk?
You’re at considerably higher risk of MASLD if you have obesity.
What else can increase your risk of fatty liver disease?
A number of conditions can increase your risk of MASLD, many of which are related to having obesity:
- Excess fat around the belly (visceral fat)
- Type 2 diabetes or prediabetes
- High blood pressure
- High cholesterol
- Family history of fatty liver disease or obesity
- Growth hormone deficiency
- Polycystic ovary syndrome
- Obstructive sleep apnea
- Underactive thyroid
- Underactive pituitary gland
Metabolic syndrome and fatty liver
Metabolic dysfunction-associated steatotic liver disease (MASLD) gets its name because people who get the condition tend to have one or several metabolic conditions.
When certain metabolic conditions happen together, medical experts call this cluster of issues “metabolic syndrome.” Metabolic syndrome raises your risk of heart disease, diabetes, and stroke. It is also linked to MASLD.
Since the term was first coined, experts have differed over the exact criteria that define metabolic syndrome. But it’s generally agreed that when you have three or more of the following conditions, you meet the criteria for metabolic syndrome:
- Excess fat around your belly area and waist
- High triglyceride levels in the blood
- Low levels of HDL cholesterol
- Elevated blood sugar levels
- High blood pressure or being on medication to lower blood pressure
Does Treating Obesity Ease Fatty Liver Disease?
When you have MASLD, it’s possible to reduce the amount of fat in your liver with weight loss and reverse your condition entirely. If you have progressed to MASH, you can make the your disease less severe and even reverse liver damage if you’re in the early stages of the disease. There are promising medications in the pipeline for treating MASLD and MASH specifically. But weight loss is – and may remain – the single best way to treat this condition.
Losing weight with fatty liver
Work with your doctor on a safe and effective weight loss plan. They'll typically advise you to:
Reduce your caloric intake. Depending upon how much weight you need to lose and other things, your doctor will probably recommend cutting back by 500 to 1,000 calories daily.
Adopt a whole-food, low-sugar diet. The quality of what you eat matters. Some studies suggest that the Mediterranean diet, which centers on fruits and vegetables, nuts, legumes, fish over meat, and healthy monosaturated fats like olive oil, is linked to improved liver enzymes and lessened fat and scar tissue in the liver. The Mediterranean diet also cuts your risk of diseases in your heart and blood vessels, which are the leading causes of death for people with MASLD.
Avoid alcohol. Even though MASLD isn’t caused by drinking, alcohol consumption can worsen your disease and speed its progression to cirrhosis.
Commit to regular exercise. Work up to getting at least 30 minutes of physical activity a minimum of five times a week. If you need to lose a lot of weight, your doctor may want you to get more than that. Exercise doesn’t have to be exhausting to be effective. Start slowly and just get your body moving with, for example, brief, regular walks. Ultimately, you’ll want to be able to do some moderate-intensity activities that’ll make you sweat and will raise your heart rate. For instance, try jogging, resistance training, Zumba, or playing pickleball.
Even without weight loss, exercise can directly benefit your liver and metabolic health. Case in point: Resistance training with dumbbells, barbells, or your own body weight directs excess glucose to your muscles and takes some of the burden off your liver. At least 135 minutes per week of aerobic exercise, research suggests, can modestly reduce the amount of fat in your liver, even if you don't lose weight.
Consider medical interventions. For years, bariatric surgery has been a popular and effective way to help people with obesity achieve significant, long-term weight loss and slow the progression or even reverse their MASLD/MASH. Now, a new generation of weight loss medications, called GLP-1 agonists, has introduced a noninvasive and highly effective way to get good results.
Semaglutide (the active ingredient in the weight loss drug Wegovy), reduces weight by an average of 12%. It is also linked to reduced blood pressure, better glucose control, and improved lipid profiles, which benefit people with MASLD/MASH.
Tirzepatide (the active ingredient in Mounjaro, another weight loss medication), is still in trials as a treatment for MASH. Evidence suggests that, along with to reducing overall body weight, it may significantly reduce fat, scarring, and inflammation in the liver itself. After a year of tirzepatide treatment, one study found that 62% of people on the drug saw their MASH resolve completely.
Only your doctor can prescribe these medications.
How much weight loss helps with fatty liver?
Losing any amount of weight is better for your liver and overall health than staying where you’re at or continuing to put on pounds. But the real benefits come when there’s significant change:
- Losing at least 5% of your body weight can reduce the amount of fat in your liver if you have MASLD.
- Losing 7% can reverse inflammation in your liver if you have been diagnosed with MASH.
- Taking off 10% of your body weight has been shown to reduce liver scarring in 85% of patients who have been diagnosed with MASH.
Recap
- Fatty liver disease is an illness in which fat builds up in the liver.
- It happens because your liver can’t process and rid itself of fat very well.
- A number of things raise the risk, but being overweight or having obesity is the most common.
- Exercising regularly and eating a healthy, calorie-controlled diet should be a primary part of your treatment plan.
- A new generation of weight loss medications called GLP-1 agonists may help people with obesity achieve significant, long-term weight loss and slow the progression or even reverse MASLD/MASH.
Does obesity cause fatty liver?
When you have obesity, it means you have a lot of extra fat all over your body, including in your liver. Obesity isn't the only cause, but it's one of the main ones.
Will losing weight get rid of fatty liver?
Yes, losing weight is one of the most important parts of treatment for fatty liver. It can even make it go away entirely.
Can fatty liver cause a big belly?
As it gets worse, fatty liver can cause inflammation and scarring in the liver called cirrhosis. This can lead to fluid buildup in your stomach called ascites, which can make your belly look bigger.
Can Ozempic help with fatty liver?
Ozempic is a semaglutide, which the FDA recently approved as a treatment for obesity under the brand name Wegovy. It can help you lower your total body fat and liver fat to improve or reverse the condition.
What happens when you gain weight with fatty liver?
If you continue to gain weight, the amount of fat in your liver may continue to build up. This may increase the risk of MASLD progressing to MASH and, potentially, liver scarring (cirrhosis) and liver failure.
Show Sources
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