Fatty liver is a growing problem that some health experts predict will be the next health tsunami. Although the overuse of alcohol and exposure to substances toxic to the liver causes fat build up on the liver, the most common cause is non-alcoholic fatty liver disease or NAFLD.
As the name implies, NAFLD is where fat builds up inside the cells that make up the liver. If you looked at an ultrasound of a fatty liver, you would see liver cells swollen with excess fat. For some people with NAFLD, fatty liver progresses no further than fat build-up, but in up to 10% of people, fatty liver advances to inflammation, a more dangerous situation that can lead to more serious complications. Also, a small percentage of people who develop inflammation progress to permanent scarring of the liver, cirrhosis. Once cirrhosis and scarring progress beyond a certain point, the only treatment is a liver transplant.
Now you know why fatty liver disease is a problem! Plus, many people have it and don’t know it since you only have symptoms once liver damage occurs. Your liver plays a key role in health. It’s responsible for processing the nutrients you take in through diet, metabolizing medications, reducing the toxic burden on your body, making clotting factors, and more. When it doesn’t work well, it affects your overall health.
Can Exercise Treat Non-Alcoholic Fatty Liver Disease?
Two of the best treatments for fatty liver is dietary change and weight loss. Insulin resistance is a common problem in people with non-alcoholic fatty liver disease. Reversing insulin resistance can have a dramatic impact on fatty liver and reduce the liver’s fatty burden. Studies show that losing weight improves insulin resistance and markers of liver function. It also reduces the amount of liver fat. For some people, weight loss alone can reverse non-alcoholic fatty liver disease.
What about exercise? Exercise helps with weight loss and weight control, so regular physical activity is beneficial for NAFLD if it leads to weight loss. In fact, research shows that losing 10% or more of total body weight can reverse non-alcoholic fatty liver disease in over 90% of people.
Does exercise have benefits for NAFLD independent of its impact on body weight? Lack of physical activity is a major risk factor for fatty liver disease and research shows even when you control for body weight, lack of exercise is a risk factor for fatty liver.
Aerobic and Resistance Training Could Improve Liver Health
In support of exercise as a treatment for non-alcoholic fatty liver disease, a study compared two groups of people with NAFLD. One group did 20 to 60 minutes of aerobic and resistance training, at least 4 days per week. When researchers compared the two groups, the group that did the exercise training, their liver health scores improved.
Another study of patients with NAFLD lowered their calorie intake and did regular aerobic exercise. At the beginning of the study, the researchers biopsied the livers of the participants and repeated it after 10 weeks on this regimen. Upon repeat liver biopsy, the amount of liver fat had declined by 30%. Although this study suggests benefits, the subjects also lost weight, so it’s hard to separate out the impact of the weight loss from the exercise.
Other studies also show a reduction in liver fat of around 30% using imaging studies or biopsy after a period of regular exercise. Combining exercise with dietary changes leads to an even greater loss of liver fat. Some studies also show that regular exercise lowers the risk of progressing from fatty liver to an inflamed fatty liver, a more serious condition known as NASH. (non-alcoholic steatohepatitis) High-intensity exercise seems to be most favorable for preventing NASH, because of its anti-inflammatory effects. Fatty liver alone isn’t as harmful as NASH, a complication that can progress to cirrhosis with permanent liver scarring and loss of function.
Other ways in which exercise may improve non-alcoholic fatty liver is by reducing insulin resistance and inflammation by its impact on fatty acid metabolism.
Combine Exercise with Dietary Changes
Since being overweight or obese is a major risk factor for NAFLD, you’ll get the most liver health benefits from combining exercise with dietary changes. In fact, weight loss is more tied to dietary changes while you need exercise for weight loss maintenance and for improving body composition. One of the smartest steps you can take to lower your risk of NAFD and reduce the amount of stored liver fat is to eliminate ultra-processed foods and sugar from your diet. If you have diabetes, control your blood glucose level, as doing so can reduce liver fat.
Of course, you should also eliminate alcohol as alcohol further places stress on the liver. Be careful with the medications you take too! The liver metabolizes medications and some medication breakdown products can cause liver inflammation.
The Bottom Line
Non-alcoholic fatty liver disease is a silent health epidemic in Western countries, partially because of high rates of obesity and inactivity. Exercise, both aerobic and resistance training, may reduce liver fat and lower the risk of progressing to NASH, a more serious complication of NAFLD that can lead to scarring. Also, know that NAFLD is often silent and you can have a substantial build-up of fat without being aware of it. If you’re overweight or obese, inactive, or have insulin resistance, your risk is much higher of developing excess liver fat.
References:
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- J Hepatol. 2012 Jul;57(1):157-66. doi: 10.1016/j.jhep.2012.02.023. Epub 2012 Mar 10.
- World J Gastroenterol. 2016 Jul 21;22(27):6318-27. doi: 10.3748/wjg.v22.i27.6318.
