In the past, many people’s first thought when liver disease was mentioned was hepatitis B. With the widespread adoption of the hepatitis B vaccine, the advancement of antiviral therapy, and improvements in public health, prevention and control of viral hepatitis have achieved notable progress. Fatty liver disease has now replaced hepatitis B as the chronic liver disease with the highest prevalence in China.
Fatty liver disease is not simply a matter of the liver “becoming fat.” Histologically, fatty liver reaches the pathological threshold when large‑droplet (or predominantly large‑droplet) steatosis appears in ≥5% of hepatocytes; this threshold specifically refers to large‑droplet steatosis and does not include small‑droplet steatosis caused by drugs, metabolic crises, or other factors. In quantitative imaging, a proton density fat fraction (MRI‑PDFF) of ≥5.6% is a commonly used imaging cutoff for hepatic fat fraction. This belongs to a different assessment system from the histological proportion of hepatocytes with steatosis and should not be simply equated.
Common types of fatty liver disease include metabolic dysfunction‑associated steatotic liver disease (MASLD), alcohol‑associated liver disease (ALD), and metabolic–alcohol associated liver disease (MetALD). In addition, fatty liver may be caused by drugs, malnutrition, pregnancy, rapid weight loss, and inherited metabolic disorders.
The misconception most in need of correction is the belief that “fatty liver does not need attention.” Early fatty liver disease often causes no obvious symptoms, and many people discover it only during ultrasound examinations at routine health checkups. If left unmanaged, some individuals may progress along the sequence of simple steatosis → steatohepatitis (MASH) → liver fibrosis → cirrhosis → liver cancer. It is important to note that although fatty liver–related liver cancer mostly occurs in people with significant fibrosis (≥F3) or cirrhosis, clinical studies have shown that a considerable proportion of patients can develop liver cancer before typical cirrhosis has formed, at the stage of moderate to advanced fibrosis; cirrhosis is not a prerequisite for cancer development. Fatty liver disease also increases the risk of hypertension, diabetes, dyslipidemia, and cardiovascular disease, serving as an alarm signal for systemic metabolic health.
Although the term “fatty liver” contains the word “fat,” it is not exclusive to people who are overweight. Individuals with normal or even low body weight may also develop fatty liver if they consume a long‑term diet high in sugar and fat, lead a sedentary lifestyle, have central obesity, or engage in blind dieting that leads to inadequate protein intake. This situation is not uncommon among people with sarcopenic obesity.
Currently, there is no specific medication suitable for all patients with fatty liver disease, and lifestyle modification remains the most effective approach: reduce consumption of sugar‑sweetened beverages, desserts, and fried foods; appropriately increase whole grains in staple foods; eat more vegetables; and ensure adequate intake of high‑quality protein from fish, shrimp, lean meat, and soy products; perform at least 150 minutes per week of moderate‑intensity aerobic exercise; and control body weight and waist circumference. According to Chinese criteria for central obesity in adults, a waist circumference of ≥90 cm in men and ≥85 cm in women marks the threshold at which metabolic risk rises significantly, and daily waist circumference should ideally be kept below these values.
If a health checkup indicates fatty liver, it is advisable to also pay attention to liver function, blood glucose, blood lipids, and blood pressure, and to undergo regular follow‑up examinations under a physician’s guidance. Do not take liver‑protective drugs, dietary supplements, or so‑called “fat‑clearing teas” on your own; whether medication is needed should be determined by a physician based on the presence of inflammation, fibrosis, and metabolic conditions. The liver does not easily “cry out in pain,” but every choice regarding diet, exercise, and daily routine affects its health.
