Circadian Rhythms in Diet-Induced Obesity Mice

For DIO studies, 8–10 week old mice were provided ad libitum access to high fat diet (HFD; 60% energy from fat; DIO Rodent Purified Diet, IPS Ltd) or normal chow (NC) for 2, 8, or 16 weeks. Prior to tissue collection, mice were placed in constant darkness (DD) and tissues collected every 4 h (n = 5–10/time-point/diet condition). In selected experiments, body temperature (T_b) and locomotor activity were recorded using radiotelemetry (Data Sciences International), and metabolic gas exchange measured by indirect calorimetry using the CLAMS system (Columbus Instruments)35 (link). Food intake was monitored using the Labmaster Metabolism Research Platform (TSE systems), with meal size and feeding events (see Supplementary Fig. S1) recorded over 6 days. For ob/ob studies, mice were maintained on NC throughout, and locomotor activity was recorded in home cages using infrared beam-break sensors.