It is widely accepted that obesity is associated with low-grade inflammation, which inhibits insulin signaling activity in adipose tissue and liver by interfering with the function of insulin receptor substrate (IRS)-1, peroxisome proliferator activated receptor (PPAR)-γ, and phosphatidyl inositol 3-kinase (PI3K)/protein kinase B (Akt) signaling (Ye, 2013). Here, INS is linked to obesity due to melanocortin 4 receptor deficiency.