Features, functions, and associated diseases of visceral and ectopic fat: a comprehensive review

Obesity is a complex, chronic, and recurrent disease marked by abnormal or excessive fat accumulation that poses significant health risks. The distribution of body fat, especially ectopic fat deposition, plays a crucial role in the development of chronic metabolic diseases. Under normal conditions, fatty acids are primarily stored in subcutaneous adipose tissue; however, excessive intake can lead to fat accumulation in visceral adipose tissue and ectopic sites, including the pancreas, heart, and muscle. This redistribution is associated with disruptions in energy metabolism, inflammation, and insulin resistance, impairing organ function and raising the risk of cardiovascular disease, diabetes, and fatty liver. This review explores the roles of visceral and ectopic fat in the development of insulin resistance and related diseases such as type 2 diabetes and metabolic dysfunction-associated steatotic liver disease. Specifically, we examine the structure and characteristics of different fat types, their associations with disease, and the underlying pathogenic mechanisms. Future strategies for managing obesity-related diseases may include lifestyle modifications, surgical interventions, and emerging medications that target lipid metabolism and energy regulation, aiming to improve patient outcomes.