Adipocytes play a crucial role in regulating energy balance and glucose homeostasis. They store excess energy, release fatty acids for fuel use, and secrete various hormones that influence metabolic processes. Adipose tissue is involved in immune response, blood pressure control, haemostasis, bone mass, and thyroid and reproductive functions. The transcriptional regulation of adipocyte differentiation is primarily mediated by peroxisome proliferator-activated receptor-γ (PPAR-γ) and CCAAT/enhancer-binding proteins (C/EBPs). Energy balance is governed by the First Law of Thermodynamics, and adipose tissue contains most of the energy stores in healthy humans. Adipocytes regulate energy balance through endocrine and non-endocrine mechanisms, including the secretion of adipokines such as leptin, adiponectin, visfatin, omentin, and tumor necrosis factor-α. Leptin, a key adipokine, modulates food intake and energy expenditure by acting on the hypothalamus and other tissues. Adiponectin improves insulin sensitivity and reduces hepatic glucose output. Visfatin and omentin also have positive effects on glucose uptake. Non-esterified fatty acids (NEFAs) released from adipocytes can reduce glucose uptake and promote hepatic glucose output. Adipose tissue serves as a lipid sink, storing large amounts of lipid without causing toxicity. Inflammation in adipose tissue is associated with obesity and type 2 diabetes, and macrophages recruited to adipose tissue contribute to insulin resistance. Genetic manipulations of adipocyte metabolism can affect global glucose homeostasis, and therapeutic strategies targeting adipocyte biology may be beneficial for metabolic diseases.Adipocytes play a crucial role in regulating energy balance and glucose homeostasis. They store excess energy, release fatty acids for fuel use, and secrete various hormones that influence metabolic processes. Adipose tissue is involved in immune response, blood pressure control, haemostasis, bone mass, and thyroid and reproductive functions. The transcriptional regulation of adipocyte differentiation is primarily mediated by peroxisome proliferator-activated receptor-γ (PPAR-γ) and CCAAT/enhancer-binding proteins (C/EBPs). Energy balance is governed by the First Law of Thermodynamics, and adipose tissue contains most of the energy stores in healthy humans. Adipocytes regulate energy balance through endocrine and non-endocrine mechanisms, including the secretion of adipokines such as leptin, adiponectin, visfatin, omentin, and tumor necrosis factor-α. Leptin, a key adipokine, modulates food intake and energy expenditure by acting on the hypothalamus and other tissues. Adiponectin improves insulin sensitivity and reduces hepatic glucose output. Visfatin and omentin also have positive effects on glucose uptake. Non-esterified fatty acids (NEFAs) released from adipocytes can reduce glucose uptake and promote hepatic glucose output. Adipose tissue serves as a lipid sink, storing large amounts of lipid without causing toxicity. Inflammation in adipose tissue is associated with obesity and type 2 diabetes, and macrophages recruited to adipose tissue contribute to insulin resistance. Genetic manipulations of adipocyte metabolism can affect global glucose homeostasis, and therapeutic strategies targeting adipocyte biology may be beneficial for metabolic diseases.