Obesity represents excess accumulation of fat in adipose tissues, which is the major risk factor for metabolic diseases including type II diabetes, hepatic steatosis and cardiovascular diseases. Importantly, numerous researches have shown that, in both
rodents and human, brown fat and the newly identified beige fat play vital roles in themogenesis and energy expenditure, as well as in glucose and lipid homeostasis as metabolic sinks, thus the enhancement of brown/beige fat functionality is considered as a novel therapeutic strategy against obesity and metabolic diseases. This review aims to address recent progress in the understanding of the anatomical, developmental, functional characteristics and regulatory network of brown and beige adipocytes, as well as discuss about the perspectives and emerging challenges.