The 2026 Levels Guide to the liver and metabolic health

From energy production to detoxification, this organ is crucial to overall well-being. Here's how to keep yours functioning at its best.

WRITTEN BY

Jessie Sebor

REVIEWED BY

Ami Kapadia, MD

Updated: 02/12/2026|10 min read

The liver is a multitasking organ that plays a prominent role in more than 500 vital bodily functions. It's a true workhouse for maintaining homeostasis and one of the most critical organs for metabolic health. In fact, every sip of liquid or bite of food we ingest is filtered by the liver. It filters out harmful substances, stores energy in the form of glycogen, regulates hormones that increase our insulin levels, and more.

It's no wonder that damage to this crucial organ can have devastating consequences for our overall health. While we often associate liver damage with alcohol or drug misuse, the most common liver disease is metabolic dysfunction-associated steatotic liver disease (MASLD), caused by fat buildup in the liver due to metabolic disorders like obesity, diabetes, high blood pressure, and high cholesterol. Today, about 25 percent of American adults suffer from this dangerous condition.

In this guide, we'll explore how the liver supports your body, why it's central to metabolic health, and practical steps you can take to keep it healthy.

What is the liver, and what does it do?

Roughly the size of a football and weighing about three pounds, the liver is the heaviest organ in our body—and one of the most critical.

Located on the upper right side of the abdomen, just below the diaphragm and above the stomach, the liver comprises two lobes. A band of connective tissue separates the larger lobe on the right and the smaller lobe on the left. Blood travels into the liver from the hepatic artery and the hepatic portal vein. Inside the liver's lobes are thousands of smaller lobes called lobules that drain bile from the liver into the small intestine.

The liver supports nearly every system in the body, playing a major role in metabolism, detoxification, and immune support. Some of its most important functions include:

• Filtering blood: The liver filters blood at a rate of more than 250 gallons a day. In fact, at any given time, about 13 percent of the body's total blood supply resides within the liver. It filters out harmful substances like drugs and alcohol, breaking them down into byproducts transported to the kidneys, where they are filtered to leave the body in our urine. Since the liver and kidney are dependent on one another in overall waste removal, when one organ is damaged, the other can be significantly impacted as well.
• Maintaining blood sugar levels: The liver helps keep blood sugar (glucose) in check. As the body's storage facility, it can stockpile glucose in the form of glycogen when blood sugar spikes and release it when it's too low.
• Turning food into energy: Although it's not part of the gastrointestinal tract, the liver is considered part of the digestive system. It helps metabolize carbohydrates, fats, and proteins, turning what we eat into energy our body can use.
• Storing energy and nutrients: The liver stores vitamins and minerals (like vitamin A, vitamin D, iron, and copper) and releases them when our bodies need them.
• Producing bile: The liver makes the digestive fluid bile, which breaks fat down into smaller particles that can be absorbed by the bloodstream.
• Supporting our immune system: The liver helps fight disease by filtering out pathogens that enter from the gut and helps regulate the response to pathogens such as viruses and bacteria.
• Regulating hormones: The liver helps regulate certain hormones, including thyroid hormone and glucagon-like peptide 1, which is related to insulin release. It is also involved in the metabolism of hormones such as estrogen and progesterone.

How is the liver related to metabolic health?

In many ways, the liver is the orchestrator of metabolic health. It regulates how we process, store, and release energy, and it helps keep blood glucose within a healthy range. When the liver is compromised, metabolic health suffers.

To regulate blood sugar, the liver acts like a warehouse manager, storing glucose in the form of glycogen. When we have an excess of glucose, the pancreas releases the hormone insulin, which both shuttles circulating glucose into cells like muscle and fat for energy and, if needed, signals the liver to stockpile what's left over as glycogen. Then, when energy demands spike and insulin levels drop, the liver turns glycogen back into glucose (a process called glycogenolysis), releasing it to ensure every part of the body stays fueled and functions properly.

The liver also has backup systems in case of a glycogen shortage, such as when fasting or eating a very low-carb diet. Low insulin levels encourage the liver to turn things like protein or fat (rather than carbs, our primary energy source) into glucose through a process called gluconeogenesis. Additionally, the liver can make ketones from fats. Ketones are an alternate fuel source that provides energy to the brain and other critical organs when glucose intake and stores are low.

While the liver works to keep blood glucose in check, diet and lifestyle significantly impact its ability to maintain that baseline. Insulin spikes can lead to lipid synthesis in the liver, causing an accumulation of triglycerides and a buildup of fat.

When our liver accumulates excess fat and inflammation, it can't function well. Even a relatively small increase in visceral fat (fat stored around the liver and other internal organs) can cause dysregulation. Visceral fat interferes with the liver's ability to regulate glucose and lipid metabolism effectively. Chronic overnutrition activates additional pathways that drive fat production independently of insulin, further perpetuating liver fat buildup. This metabolic overload promotes oxidative stress, which can damage liver cells, leading to a vicious cycle of further damage and disease.

One of the most important ways to keep our liver healthy is to limit sugar intake, and fructose in particular. That's because while nearly every cell in our body can process glucose from food, the liver is the only organ that can process significant amounts of fructose. Fructose is processed in the liver faster than glucose and is more likely to contribute to fat production. When consumed in large amounts over time, fructose activates an enzyme called aldolase B, which breaks it down into smaller molecules. These molecules are further converted into pyruvate and acetyl-CoA, key building blocks for fat production. This can disrupt normal metabolism, leading to imbalances in lipid levels and fat in the liver. Excessive fructose intake also increases the production of uric acid in the liver and intestine, causing inflammation.

What can go wrong with liver and metabolic health?

The liver can be impacted by genetic diseases, infections (like hepatitis A, B, or C), autoimmune conditions, and cancer. Accumulation of toxins, including alcohol and medications, can lead to serious damage and even liver failure in extreme cases.

In addition to the above conditions that can affect the liver, metabolic dysfunction has a significant impact on liver health. The leading cause of liver dysfunction in the United States is metabolic dysfunction-associated steatotic liver disease (MASLD). MASLD affects one-quarter to one-third of adults in America and was known as non-alcoholic fatty liver disease (NAFLD) until an official name change in 2023 to acknowledge the disease's roots in metabolic dysfunction. In MASLD, the liver stores excess fat, accounting for more than 5 to 10 percent of the liver's weight. While some fat in the liver is normal—remember, it can use that fat to create glucose—too much can cause problems. MASLD can lead to chronic liver inflammation (hepatitis) and increase the risk of pregnancy complications, permanent scarring of the liver (cirrhosis), liver failure, and liver cancer.

MASLD is diagnosed when someone not only has an excess of fat in the liver (more broadly called steatotic liver disease) but also at least one of five cardiometabolic risk factors:

1. Overweight, obese, or a high waist circumference: This is defined as having a body mass index (BMI) greater or equal to 25 or having a waist larger than 80 cm (31.5 inches) for women or 94 cm (37 inches) for men. Note: These numbers can shift slightly based on someone's ethnic background.
2. Elevated blood sugar levels: Anyone with Type 2 diabetes or who has any of the following is at risk: fasting blood sugar of 100 mg/dL or higher, oral glucose tolerance test of 140 mg/dL or higher, or HbA1c level of 5.7 percent or higher.
3. High blood pressure: This includes anyone with a blood pressure of 130/85 mmHg or higher, as well as anyone who is being treated with medication for hypertension.
4. High triglycerides: A type of fat found in your blood, triglycerides are crucial for energy storage. However, an excess amount can lead to metabolic disorders. Anyone with elevated triglycerides or who is on medication for elevated triglycerides is at risk.
5. Low HDL cholesterol: HDL cholesterol helps remove excess cholesterol from the arteries and transports it to the liver for removal from the body. Low HDL cholesterol is defined as 40 mg/dL or lower for men or 50 mg/dL or lower for women.

Many people with MASLD don't know they have it. The condition can exist for years without physical symptoms. That's why it's essential to stay on top of annual physicals and track your health and these risk factors to identify the disease before it leads to serious complications.

What's the connection between insulin resistance and liver disease?

The majority of people (64 percent, according to one study) with Type 2 diabetes also have MASLD. That's because insulin resistance and MASLD often influence each other in a vicious cycle.

In Type 2 diabetes, the body at large and the liver specifically become resistant to insulin, meaning they don't respond appropriately to the hormone. Insulin resistance can encourage the liver to store more fat, leading to a build-up within the organ. Likewise, as fat accumulates within the liver, it can worsen insulin resistance, and the conditions exacerbate each other.

How can I check my liver health?

Since liver conditions like MASLD often have no symptoms, you need diagnostic testing to get a snapshot of liver function. At your annual physical, your healthcare provider will likely order a comprehensive metabolic panel (CMP). The CMP tests several substances, many of which are indicators of liver health. If any readings are out of the normal range, your healthcare provider may order additional liver function tests.

CMP tests connected to liver health include:

Bilirubin: A product that the liver makes by turning red blood cell waste into bile. High or low bilirubin levels can indicate your liver isn’t functioning well.
Normal Range: 0.2 to 1.3 mg/dL

Albumin: A protein made by your liver that helps support blood circulation. Low albumin can indicate issues with your kidneys, liver, bowel, or thyroid, while high albumin most often occurs when you’re dehydrated.
Normal Range: 3.5 to 5.5 g/dL

Liver enzyme: ALP, ALT, and AST are proteins that support chemical reactions in the liver. High readings can mean the liver is inflamed, causing enzymes to leak into the bloodstream.
Normal Range: ALP: 44 to 147 IU/L, ALT: 4 to 36 U/L, AST: 8 to 33 U/L

Total protein: This is the total amount of albumin as well as globulin in your blood. Because the liver makes these proteins, low levels can signal that the organ isn’t working well.
Normal Range: 6.0 to 8.3 g/dL

Glucose: While this test doesn’t directly measure liver function, low levels without diabetes can be a sign of liver disease. High glucose levels can indicate insulin resistance and diabetes.
Normal Range: 70 to 99 mg/dL

In addition to abnormal CMP results, other risk factors of MASLD—all of which are typically measured at an annual exam—can give you a fuller picture of your liver health. These include height, weight, waist circumference, blood pressure, triglyceride levels, and cholesterol.

How to keep your liver healthy

A healthy liver is essential to a healthy body, and if you care about metabolic health, you're likely already doing things to support your liver. Research shows that even if you have MASLD, lifestyle choices can stop or even reverse the progression of the disease. Here are a few measures you can take:

• Stay proactive: If you have any of the risk factors for MASLD, talk to your doctor about its impacts on your liver and what you can do to mitigate your risk. No matter your health status, staying on top of regular physicals, getting annual blood work, and measuring the markers of metabolic health can help you identify issues before they snowball into disease.
• Choose a healthy diet: Too much fructose in your diet can lead directly to an overaccumulation of fat in the liver. Check nutrition labels for added sugars.
• Limit alcohol: Alcohol breakdown creates a toxin that taxes the liver, and even moderate drinking has health risks. Consider DIY alcohol alternatives to lower your consumption.
• Exercise regularly: Research has shown that 150 minutes of moderate to intense exercise each week can significantly reduce fat in the liver.
• Be mindful of supplements and medications: Herbal and dietary supplements account for 20 percent of liver damage. Medications like acetaminophen (Tylenol), statins to lower cholesterol, and other drugs can cause liver injury as well. Check with your healthcare provider before taking any supplement or medication—even if it's available over the counter.

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