[Obesity, Metabolic Syndrome, and Fatty Liver Disease].

Obesity, metabolic syndrome, and fatty liver disease, particularly nonalcoholic fatty liver disease(NAFLD), are significant health issues in current society. These conditions are linked to lifestyle changes such as overeating and lack of exercise, and their prevalence is increasing. Obesity is defined using body mass index(BMI), with a BMI of 25 kg/m² or higher considered obese in Japan due to the higher health risks in this population. Obesity significantly increases the risk of diabetes, hypertension, dyslipidemia, cardiovascular disease, and cancer. Metabolic syndrome involves visceral fat accumulation along with high blood glucose levels, dyslipidemia, and hypertension. NAFLD, which is related to metabolic abnormalities such as obesity and diabetes, can progress to non-alcoholic steatohepatitis(NASH), cirrhosis, and liver cancer. Recent concepts, such as metabolic dysfunction-associated fatty liver disease and metabolic dysfunction-associated steatotic liver disease, provide new diagnostic criteria that better identify high-risk patients. The effective management of these diseases involves lifestyle changes and targeted medical treatments. Ongoing research and new diagnostic criteria are expected to improve prevention, diagnosis, and treatment and enhance patient outcomes and quality of life.