Brown adipose tissue sustains thermogenesis through metabolic flexibility in glucose utilization

Diets included a normal chow diet (NCD; 13% fat per kcal, 25% protein per kcal, 62% carbohydrate per kcal) or a series of compositionally-matched diets including a low-fat diet (LFD; 10% fat per kcal, 20% protein per kcal, 70% carbohydrate per kcal), regular-fat diet (RFD; 20% fat per kcal, 20% protein per kcal, 60% carbohydrate per kcal), moderate-fat diet (MFD; 40% fat per kcal, 20% protein per kcal, 40% carbohydrate per kcal), high-fat diet (HFD; 60% fat per kcal, 20% protein per kcal, 20% carbohydrate per kcal), and very high-fat diet (VHFD; 72% fat per kcal, 20% protein per kcal, 8% carbohydrate per kcal).

Mice were previously reared at room temperature (22-24˚C) and acclimated to each diet for 3 days before transitioning to temperature-controlled chambers.