To investigate whether IL-25 protected mice with DIO from obesity and metabolic associated disorder by stimulating the development of beige fat, WT (UCP1+/+) and UCP1-null (UCP1−/−) mice were fed with an HFD for 12 weeks and then injected with IL-25 (1 μg/mouse) or vehicle for 14 days. Here, UCP1 is linked to obesity due to melanocortin 4 receptor deficiency.