Non-Alcoholic Fatty Liver: How Obesity Leads to Fatty Liver Disease

Non-Alcoholic Fatty Liver: How Obesity Leads to Fatty Liver Disease

Non-Alcoholic Fatty Liver Disease (NAFLD) is a condition where fat builds up in the liver. If it gets worse, it can harm the liver cells and cause liver damage. NAFLD is common and affects about 1 in 3 adults in the United States. We don't know precisely how NAFLD develops yet, but we do know that being overweight is strongly linked to it. NAFLD usually doesn't show obvious signs but can increase the risk of other health problems like metabolic and heart diseases. NAFLD is becoming more common worldwide and is the top reason for needing a liver transplant. It's also the fastest-growing cause of liver cancer. So, it's essential to prevent, find, and treat NAFLD.

What Are the Common Symptoms of Non-Alcoholic Fatty Liver Disease?

NAFLD usually doesn't show signs, so most people don't know they have it unless they get tested. Doctors often check the levels of certain substances in the blood to see if someone has NAFLD. If these levels are too high, the doctor may order a unique picture of the liver to make sure. In some cases, a small piece of the liver may be taken to check how bad the disease is.


NAFLD is divided into non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH). NAFL means there's fat in the liver without any scarring or swelling. If this fat build-up isn't treated and gets worse, it can harm the liver cells and lead to a condition called NASH. NASH is when there's scarring or swelling in the liver. Most people with NAFL never have any more problems, but around 20-30% of cases develop into NASH. In rare cases, NASH can cause cirrhosis (when the liver gets damaged and scarred), liver failure, or liver cancer.


Even though NAFL and NASH usually don't have noticeable signs, some people may constantly experience pain in the upper right side of their belly or feel tired. If the disease gets worse, people with advanced cirrhosis or liver failure may have these symptoms:


  • Feeling very tired, weak, or exhausted

  • Losing weight without trying and having no appetite

  • Having fluid build up in the belly, which can make it swell (called ascites)

  • Swelling in the feet or legs

  • Skin or eyes turning yellow.

  • Seeing spider-like blood vessels on the skin

  • Feeling confused or not thinking clearly


How Does Obesity Lead to Non-Alcoholic Fatty Liver Disease?

Obesity is the most common and well-known risk factor for developing NAFLD. About 50-90% of people with obesity also have NAFLD. Studies have found that the higher a person's BMI (body mass index), the greater their risk of having NAFLD. For example, someone with a BMI between 30 and 32.5 is 5-9 times more likely to have NAFLD, while someone with a BMI between 37.5 and 40 is 10-14 times more likely to have NAFLD. The relationship between obesity and NAFLD goes both ways, but we still don't fully understand it. Having a higher BMI increases the chances of getting NAFLD, and having NAFLD also makes it more likely to gain weight. Many of the same things that contribute to weight gain, like insulin resistance, unhealthy eating habits, and not being physically active, also increase the risk of getting NAFLD.

Insulin Resistance

Insulin resistance happens when our cells stop responding appropriately to a hormone called insulin, which is important for storing energy. If this problem worsens, it can lead to type 2 diabetes and other metabolic diseases. In the liver, insulin resistance can cause cells to make more fat and break down less fat, leading to NAFLD. And guess what? NAFLD can make insulin resistance worse, creating a cycle of metabolic problems. Research shows that about 70% of people with type 2 diabetes also have NAFLD.

Unhealthy Dietary Habits

Eating a lot of processed foods, especially ones with lots of unhealthy fats and added sugars, has been connected to the development of NAFLD. A recent study found that people who consumed moderate to high amounts of ultra-processed foods had a greater chance of getting NAFLD.

Sedentary Lifestyle

Spending a lot of time sitting and physically inactive has been strongly linked to NAFLD. The longer someone sits and the less they engage in physical activity throughout the day, the higher their chances of developing NAFLD.

Non-Alcoholic Fatty Liver Disease Prevention and Treatment

Although no medications are approved by the FDA specifically for treating NAFLD, the good news is that you can prevent and treat NAFLD by changing your lifestyle and losing weight.

Weight Loss

Research has found that losing more than 10% of your body weight can help reduce fat in the liver and improve liver scarring. However, even a 3-5% weight loss can start improving the risk factors associated with NAFLD. Whether you achieve this weight loss through lifestyle changes alone or with the help of medications or weight loss surgery, losing weight is currently the most effective treatment option to improve or even reverse NAFLD for most people.

Dietary Changes

Various diets have been studied to reduce the severity of NAFLD, but the best strategies have similar principles. Making dietary changes that focus on reducing processed foods and drinks, especially those with lots of added sugars and unhealthy fats, and replacing them with whole, unprocessed foods is a good approach. This includes eating plenty of vegetables, fruits, lean proteins, high-fibre starches, and healthy fats in olive oil, nuts, and fatty fish. One helpful way to make these changes more accessible is to use the plate method as a guide. It can feel overwhelming, but starting with these adjustments is a great way to improve your diet.

Physical Activity

Many studies have found that aerobic exercises (like running or swimming) and resistance training exercises (like lifting weights) effectively improve NAFLD. Regular physical activity can help improve NAFLD by reducing insulin resistance, reducing inflammation, and even without weight loss, it can still be beneficial. It's important to remember that being physically active can positively impact NAFLD, regardless of whether you lose weight.


Although there are currently no medications approved by the FDA specifically for treating NAFLD, there are ongoing studies on this topic. GLP-1 medications, such as Wegovy, Saxenda, and Ozempic, have shown promise in improving NAFLD severity. This is likely because they can help with weight loss and insulin resistance. Researchers are studying these medications to determine their potential use in treating NAFLD.

Managing Obesity for Better Health

NAFLD is a widespread disease that can raise the chances of liver damage and other metabolic problems. Although we don't fully understand how obesity and NAFLD are linked, we do know that being overweight greatly increases the risk of getting NAFLD. The most effective way to treat NAFLD is by losing weight.


Losing weight can be difficult for various reasons, but a program called Weight Loss Coach can assist you.


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