Patient-Friendly Explanation

Brown fat is a special type of body fat that burns calories to produce heat, unlike regular white fat which stores energy. It is activated by cold temperatures and plays a natural role in regulating body weight and metabolism.

Clinical Definition

Brown adipose tissue (BAT) expresses uncoupling protein 1 (UCP1), which dissipates the mitochondrial proton gradient to generate heat instead of ATP — a process called non-shivering thermogenesis. BAT activity is inversely correlated with BMI and age, and its metabolic activity can be stimulated by cold exposure, β3-adrenergic agonists, and certain dietary factors. Pharmacological activation and expansion of BAT are emerging therapeutic targets for obesity.

Why It Matters

Understanding brown fat helps explain individual differences in calorie burning and points toward future treatments that may harness BAT to support weight loss.