1 in 3 Americans Have Fatty Liver Disease, Even If They Look Healthy 🥩 The Gut Insiders Ep 18

Main Ideas

• Fatty liver is common and often goes unnoticed. The physician cites a U.S. survey of about 12,000 adults in which roughly 35% had fat in their liver. Most people with fatty liver do not know they have it. It can also occur in people who look healthy or are thin: about one in five people with fatty liver are lean.
• It is often a metabolic condition, not just an alcohol-related one. The discussion connects fatty liver with insulin resistance and other metabolic risks, including prediabetes, type 2 diabetes, high blood pressure, abnormal triglycerides, and low HDL cholesterol.
• How fat can accumulate in the liver: The speakers use a “garage” analogy. Fat cells store excess energy, but storage capacity varies. When fat storage is overwhelmed—or insulin regulation is disrupted by inflammation—fat can spill into places not meant to store it, including the liver, muscles, and pancreas. This “lipotoxicity” can interfere with blood-sugar regulation. Fat in the liver may also contribute to the liver releasing too much sugar into the bloodstream.
• Why it matters: Fatty liver can progress to liver inflammation and scarring (cirrhosis), which cannot be reversed. The speakers also emphasize broader metabolic and cardiovascular concerns: they cite cardiovascular disease as the leading cause of death among people with fatty liver and describe their risk of a cardiovascular event as elevated.
• Normal-looking blood work does not necessarily rule it out. A patient example illustrates how someone thin and apparently healthy may have signs of insulin resistance and fatty liver. In the example, a brown, velvety-looking skin patch—acanthosis nigricans—prompted further evaluation. The patient’s standard liver enzymes were technically within range but toward the high end; follow-up testing found liver fat without scarring.

Who Should Consider Getting Checked

The physician suggests discussing screening with a doctor if any of the following apply:

• You have prediabetes or type 2 diabetes.
• You have two or more of the following: a larger waistline, high blood pressure, high triglycerides, low HDL cholesterol, or high blood sugar.
• A previous scan mentioned fatty liver.
• Your liver enzymes are abnormal.
• You have a family history of cirrhosis or a history of heavy alcohol use.

A FIB-4 score can be calculated from routine blood work using age, two liver enzymes (AST and ALT), and platelet count. In the discussion:

• A score below 1.3 is described as low risk, with reassessment in a year or two suggested.
• A score above 1.3 is a reason to consider a FibroScan.
• A very high score—around 2.67 or higher in the example—or high liver stiffness may warrant discussion with a liver specialist.

A FibroScan is described as a brief, non-painful test that can assess liver fat and stiffness, the latter being an indicator of scarring. Screening steps and interpretation should be discussed with a clinician.

Five Approaches Discussed to Reduce Liver Fat

1. Move regularly. The physician cites evidence that 150 minutes per week of brisk walking can make people 3.5 times more likely to reduce liver fat, even without weight loss. One practical example is 30 minutes, five days a week. Other forms of activity can complement walking; the speakers distinguish cardiovascular activity from resistance training while valuing both.

2. Cut sugary drinks and other liquid sugars. Whole fruit is not presented as a cause of fatty liver; its fiber, food structure, and other components may be beneficial. The concern is sugar separated from whole foods, including sugary drinks. A study described in the episode found that three cans of regular soda a day for six months doubled liver fat compared with milk, diet soda, or water, without a difference in total body fat.

3. Drink coffee, preferably without added sugar. The physician cites observational evidence associating coffee drinking with about a 30% lower risk of fatty liver and cirrhosis. The speakers caution that sugary additions may undermine the benefit.

4. Reduce or avoid alcohol if you have fatty liver. They say even a level often considered moderate—about two drinks a day—may interfere with reversing fatty liver. Their stated takeaway is that less is better and none is best for people with the condition.

5. Follow a plant-forward “green Mediterranean” pattern. The episode describes the DIRECT PLUS trial, in which a more plant-based Mediterranean diet nearly doubled liver-fat loss compared with the standard Mediterranean approach, reducing liver fat by roughly half. Suggestions include:

   • Choose whole grains rather than refined grains.
   • Favor unsaturated fats such as nuts, seeds, avocado, and extra-virgin olive oil.
   • Include walnuts and green tea.
   • Limit red and processed meat.
   • Favor whole plant foods that support gut bacteria.

For people with excess weight, weight loss is also described as a particularly powerful lever; the other approaches can be used alongside it. The speakers note that the five lifestyle changes helped their thin patient’s blood sugar and triglycerides improve and her liver-fat scan return to the normal range, without weight loss.

Gut Microbiome Research

• The episode discusses a newly published mouse study in which gut microbiome changes appeared to transfer leaky gut and fatty liver between mice, despite the animals receiving the same diet. Transferring microbes from healthy mice had the opposite effect in the experiment.
• The study also tested pasteurized Akkermansia (the name is rendered inconsistently in the subtitles). The speakers say it improved the gut barrier and reduced liver fat in the mice.
• They stress that these are animal findings and need confirmation in humans; the discussion does not establish that gut bacteria cause fatty liver in people.
• Dr. B also discusses a prebiotic product from his company, 38TERA DMN, and says a study found changes in short-chain fatty acids and Akkermansia levels. He explicitly notes that the product has not been studied as a treatment for fatty liver.

Speakers and Sources Featured

Speakers

• Chuck — host/co-host.
• Dr. Will Bulsiewicz (“Dr. B”) — physician and guest.

Research and Other Sources Mentioned

• A CDC national survey using FibroScan-type testing, cited for the estimate that about 35% of adults had liver fat.
• A mouse microbiome study published in the journal Gut.
• The DIRECT PLUS clinical trial of a green Mediterranean diet.
• Observational research on coffee and liver outcomes.
• A study comparing regular soda with milk, diet soda, or water.
• “Megan,” an anonymized clinical patient example described by Dr. B.
• A study of 38TERA DMN mentioned by Dr. B; he states it was not a fatty-liver study.