Fatty liver disease is rarely a standalone diagnosis: A doctor breaking the news of positive test results will probably be someone you’re already seeing for another chronic condition. It can be either frustrating or heartening, then, to hear that the best treatment plan is quite simple: Weight loss.
But how much?
There’s no one-size-fits all number that applies to everyone. “But we know that even 7% to 10% of weight loss can have a tremendous impact on reversing fatty liver disease before it gets to the point of cirrhosis of the liver,” says Allison Arnett, a dietitian at the University of New Haven.
And there’s something even more important that your doctor may not mention: What really matters is that those pounds don’t boomerang back.
Here’s what to know if it’s time for you – and your liver – to lose weight.
Even when not lined with fat, the liver isn’t a glamorous organ. The cone-shaped structure performs over 500 near-constant functions critical to our survival, making it one of the largest consumers of energy in the body, as well as the largest internal organ. It produces bile to aid in fat digestion. Filters toxins from the bloodstream. Regulates blood sugar levels to keep energy use efficient. Synthesizes proteins crucial for blood clotting and immune responses.
When too much fat builds up in the liver, as is the case for roughly 1 in 4 adults worldwide, all of these processes can become strained. The liver’s fat stockpile takes up 5% to 10% of the organ’s total weight in people with metabolic dysfunction-associated steatotic liver diseases (MASLD, formerly called nonalcoholic fatty liver disease or NAFLD).
We tend not to think too much about our liver, especially if alcohol abuse isn’t an issue. MASLD is easier to ignore than other more aggressively measured metrics like blood pressure, blood sugar, and cholesterol because the liver doesn’t complain when it’s hurting. But we hurt it daily with unhealthy choices.
If your weight is rising over time – and particularly if you carry excess weight in your midsection, aka visceral fat – you’re almost certainly dealing with some level of fatty liver.
Lifestyle – including “a diet high in processed foods, added sugars, saturated fats, and refined carbohydrates – and/or genetic susceptibility set the stage for MASLD, Arnett says.
That’s why there’s no MASLD treatment plan that doesn’t include lifestyle change and weight loss.
Even resmetirom, the lone medication approved by the FDA to treat liver scarring in a later-stage form of MASLD called metabolic dysfunction-associated steatohepatitis (MASH), has only ever been studied in tandem with lifestyle intervention, says James Lewis, MD, director of hepatology at MedStar Georgetown University Hospital in Washington, D.C.
A quick look at the science shows there’s no shortage of evidence that weight loss, often via dietary change and physical activity, is the most effective way to reverse pre-cirrhosis MASLD.
For instance, a 2021 review of studies on weight loss and MASLD found that 85% to 90% of people with MASH who lost 10% of their starting body weight or got bariatric surgery (a procedure that on average cuts 20% of initial weight) saw their MASH resolved as soon as a year later.
That same year, a different analysis of 43 studies showed that with each additional kilogram of weight a patient lost, levels of liver enzymes that often soar in MASLD and MASH dropped. Inflammation, in particular, calmed down more and more as the pounds notched downward. The authors put it this way in their conclusion: “Clinically significant improvements in NAFLD [now called MASLD] are achieved even with modest weight loss, but greater weight loss is associated with greater improvements.”
There are many routes to weight loss, including changing what or how much you eat, becoming more active, taking prescription weight loss medications, or bariatric surgery. Together, the research shows that sustained weight loss to any degree can reverse some amount of fatty liver disease. That’s partly due to one of the liver’s superpowers: It’s excellent at repair and regeneration.
As many people know all too well, losing weight requires adjusting both what you eat and how active you are. And with that comes all kinds of health perks for your whole body.
For your liver, weight loss frees up and improves metabolic resources the organ uses to clear out fat buildup. What’s more, because conditions like type 2 diabetes can ebb and flow along with relationship with fatty liver disease, efficient and effective dietary change and weight loss – with or without help from tools like bariatric surgery and GLP-1 agonist weight loss drugs such as semaglutide (Wegovy) and tirzepatide (Zepbound) – sometimes improves multiple health concerns at once. When additional interventions are recommended, it is typically to reverse liver damage and prevent further decline and health problems.
Specific dietary changes matter, too, especially when it comes to maintenance after weight loss.
“Fatty foods don’t put fat in your liver,” Lewis says. “Weight loss by itself – it’s important, but it’s unlikely that it’s going to get you the same results as combining it with a low-carb diet and exercise regimen.”
That includes cutting down on sugary drinks or foods that lack nutritional value – including alcohol (even though MASLD isn’t directly caused by alcohol, it still has empty calories and even moderate amounts may cause liver damage) and sweet beverages. You’ll also want to limit starchy foods like white bread, white rice, and potatoes in favor of fiber-packed produce.
Why low-carb? Foods that pack a lot of simple carbs can trigger your body to store fat and your liver’s involvement in that process will inevitably lead to more fat stored in the liver itself. It’s all part of the metabolic syndrome/type 2 diabetes/obesity cycle.
And while the occasional processed treat is still OK, “that style [of] diet in the long term is going to be what can help prevent – and, depending on when a patient recognizes that they have fatty liver, reverse – some of the symptoms,” Arnett says.
Because MASLD rarely exists in a vacuum, the goals and priorities of diet and weight loss, particularly in early stages, can vary widely. It’s almost always up to you and your doctor to plan it together.
Most important, Lewis says, is that a treatment plan feels manageable and sustainable. Fatty liver disease builds up “over years and decades,” Lewis says. “We can’t expect somebody to immediately be able to diet away half their life.”
That’s why “long term” is the key here, as your lifestyle choices going forward are going to determine if your fatty liver – and its related conditions – are optimally managed for the rest of your days. Once it’s controlled, your lifestyle will strongly influence whether it stays that way.