a, b Body weight curve and body weight change of UCP1−/− mice on a high-fat diet administered daily with either a jelly containing vehicle (control) or BIBO3304 for 8 weeks. Data are mean ± s.e.m, n = 6 per group (control: open circle; BIBO3304: filled circle). p values by two-way repeated measures ANOVA. c Whole-body fat mass of vehicle- and BIBO3304-treated UCP1−/− mice on a HFD determined by DEXA at baseline and after 2 weeks of treatment. d Dissected weights of individual WAT from inguinal (WATi), epididymal (WATe), mesenteric (WATm), retroperitoneal (WATr) and total weights of these 4 depots (WATsum) at cull. e Whole-body lean mass of vehicle- and BIBO3304-treated UCP1−/− mice on a HFD determined by DEXA at baseline and after 2 weeks of treatment. Data are mean ± s.e.m, n = 6 per group (control: open red; BIBO3304: red). p values by two-sided t test (c, d, e). f, g Energy expenditure, h, i RER of vehicle- and BIBO3304-treated UCP1−/− mice on a HFD over a 24 h course during an indirect calorimetry study at 13 weeks of age. Data are mean ± s.e.m, control n = 6 (open circle), BIBO3304 n = 5 (filled circle). p values by two-way repeated measures ANOVA. j Temperature measured by infra-red camera of BAT and lumbar back regions of HFD-fed UCP1−/− mice given vehicle or BIBO3304 jelly at 11 weeks of age. Data are mean ± s.e.m, control n = 6 (open red), BIBO3304 n = 5 (red). p values by two-sided t test within the same region. k Glucose levels in an intraperitoneal glucose tolerance test (GTT) in vehicle- and BIBO3304-treated UCP1−/− mice on a HFD at 13 weeks of age. Data are mean ± s.e.m. n = 6 per group (control: open circle; BIBO3304: filled circle). p values by two-way repeated measures ANOVA. ns non-significance. Source data are provided as a Source Data file.