Exercise is beneficial for every organ in your body, but you hear less about its impact on your liver, one of the largest and busiest organs in your body. Your liver, which weighs around 3 pounds and lies in the upper right quadrant of your abdomen, has a long list of tasks it must perform. For example, it produces bile that aids in digestion, breaks down toxins, metabolizes medications, makes proteins that carry cholesterol and fat throughout the body, produces blood-clotting factors, stores glucose and glycogen, and more. These functions are so critical that you need a healthy liver to survive.
Unfortunately, the liver is susceptible to toxins, including alcohol and medications, but there’s another cause of liver disease that affects a whopping 1 out of 4 people in Western countries. It’s called non-alcoholic fatty liver disease (NAFLD), an acronym that distinguishes it from liver disease caused by overuse of alcohol. However, this type of liver problem has another name, metabolic associated fatty liver disease (MAFLD) because it’s associated with insulin resistance and metabolic dysfunction. However, MAFLD is the same entity as NAFLD.
When you have MAFLD, fat builds up in your liver. In the early stages, it causes no symptoms and you probably aren’t aware you have it. However, 20 to 30% of people with NAFLD progress to a more advanced stage called nonalcoholic steatohepatitis. (NASH) Once NASH sets in, the fatty portions of the liver become chronically inflamed. Some people with NASH develop liver scarring, a condition known as cirrhosis. Once the liver scars, that portion of the liver no longer functions. A small percentage of people who start with MAFLD progress to chronic cirrhosis and require a liver transplant to survive. That’s why reversing fatty liver is so important.
Exercise as a Treatment for MAFLD
The main lifestyle treatment that physicians recommend for MAFLD is weight loss. Losing as little as 7% of body weight can reduce the amount of fat deposited in the liver. However, research from Trinity College in Dublin finds that aerobic exercise may be as effective as weight loss for treating MAFLD. Until now, few studies have looked at aerobic exercise alone as a treatment for MAFLD. Fortunately, this one did and the results are encouraging.
For the study, 16 subjects with biopsy-confirmed MAFLD took part in a 12-week aerobic exercise program. Eight additional subjects did not exercise and served as a control group. As you might expect, the participants who exercised improved their aerobic fitness by 17% relative to the control group. From the perspective of liver health, aerobic exercise was a success too. Almost 60% of the group who exercised reduced the amount of liver inflammation and fibrosis, as confirmed by a repeat liver biopsy. They also experienced these benefits without losing weight, although they shed body fat and fat around their waist. Another change in the exercise group was a reduction in hepatocyte ballooning, the breakdown of liver cells. That’s favorable for liver health.
This isn’t the first study to look at how exercise affects a fatty liver. A 2018 study found that physical activity correlates with the severity of fatty liver disease independent of a person’s body weight. If two people have MAFLD and one is more physically active than the other, the less active person is likely to have more severe disease even if they weigh the same. Furthermore, studies show aerobic AND high-intensity resistance exercise lower liver fat content. Therefore, getting a little sweaty is healthy for your liver!
Why is exercise so effective at reducing liver fat? Exercise increases the rate at which fatty acids are oxidized and converted to energy, so the fatty acids aren’t available for the liver to convert to liver fat. Exercise also improves peripheral insulin sensitivity and insulin resistance is a driving force behind MAFLD. When cells are insulin resistant, they release more fatty acids into the bloodstream and the liver absorbs them and stores them as liver fat. Therefore, improving insulin sensitivity is key to reducing fat build-up in the liver. There are medications, like metformin, that improve insulin sensitivity, but exercise does it without the side effects of prescription medications.
There is one caveat with exercise: you have to keep doing it! After some time had passed, the participants in the study let their exercise habit fall by the wayside and they reversed the positive changes to their liver. So, consistency is important, and that’s where many people fall short. They cannot maintain healthy lifestyle habits over the long term. You can’t do it for a few weeks, stop, and hope the fat won’t return. It must be ongoing.
Other Lifestyle Tips for Reversing Fatty Liver
Exercise and weight loss are the two most effective lifestyle approaches to reducing fat on the liver. Watch the composition of your diet too. Eliminate sugar and refined carbohydrates and replace them with nutrient-dense, whole foods, including non-starchy vegetables and fruits. Doing this will improve insulin sensitivity and help with weight loss. Avoid alcohol, especially if you have signs of liver inflammation, and monitor your liver enzymes closely if you take medications, as the liver breaks down most medications.
You’re at high risk for MAFLD if you have type 2 diabetes or are obese. If you fall into one of these categories, talk to your physician about monitoring your liver with blood tests that measure liver enzymes and a screening ultrasound.
The Bottom Line
Exercise, even without weight loss, helps reverse MAFLD. In fact, exercise may be more effective than weight loss alone. However, the combination of weight loss and exercise is best, as both factors improve insulin sensitivity. The earlier you treat MAFLD through lifestyle, the less likely you are to experience complications such as inflammation or cirrhosis. Just because MAFLD doesn’t cause symptoms doesn’t mean it’s not serious. Know what your risk factors are and if you already have it, start exercising consistently.
References:
- Philip O’Gorman, Sara Naimimohasses, Ann Monaghan, Megan Kennedy, Ashanty M. Melo, Deirdre Ní Fhloinn, Derek G. Doherty, Peter Beddy, Stephen P. Finn, J. Bernadette Moore, John Gormley, Suzanne Norris. Improvement in histological endpoints of MAFLD following a 12-week aerobic exercise intervention. Alimentary Pharmacology & Therapeutics, 2020; DOI: 10.1111/apt.15989.
- Gene Expr. 2018; 18(2): 89–101. Published online 2018 May 18. doi: 10.3727/105221617X15124844266408. PMCID: PMC5954622.
- Med Sci Sports Exerc. 2017 Sep; 49(9):1834-1841.
- JHEP Rep. 2019 Dec; 1(6): 468–479. Published online 2019 Nov 5. doi: 10.1016/j.jhepr.2019.10.008.