Male Foxp3-YFP-Cre⁺ (WT) and IL-10^fl/fl mice crossed to Foxp3-YFP-Cre⁺ (conditional knockout, CKO) were placed on 60% HFD for 18–20 weeks prior to metabolic analysis. (A) Bar graph indicating body weight of 28-week-old HFD-fed WT and CKO mice. (B) Bar graph showing fasting plasma insulin levels in WT and CKO mice. (C) Bar graph showing fasting blood glucose levels in WT and CKO mice. (D) Bar graph showing the homeostatic model assessment of insulin resistance (HOMA-IR) in WT and CKO mice. (E and F) An i.p. glucose tolerance test (GTT) was performed on WT and CKO mice. The graphs indicate plasma insulin and blood glucose levels in mice over time after i.p. glucose injection. Bar graphs indicate the area under the curve (AUC) for both groups. (G) Gross appearance, inguinal WAT (iWAT), epididymal visceral WAT (VAT), and livers of 28-week-old HFD-fed WT and CKO mice. (H) Photographs and quantification of the colon length in WT and CKO mice after 18–20 weeks on HFD. Histology showing H&E staining of colon sections from the WT and CKO mice. (I) Graph showing body weight (BW) and lean and fat mass in grams of WT and CKO mice as measured by EchoMRI. (J–L) Food intake in grams per kilogram lean mass (LM), total activity in meters, and respiratory exchange ratio (RER) in light, dark, and total as measured by Promethion Multiplexed Metabolic Cage System during 48-hour total duration. (M) Western blots showing PRDM16 expression in total iWAT from WT and CKO mice fed HFD for 18–20 weeks. Each lane represents 1 mouse. β-Actin loading control is shown. Data are presented as means ± SEM and are from 3 independent experiments with 3–8 mice per group, where each dot represents 1 mouse, and an unpaired 2-tailed Student’s t test or 1-way ANOVA was performed to determine significance. *P value of less than 0.05.