LEP and obesity due to melanocortin 4 receptor deficiency: This is evidenced by findings that long-term HFD-fed mice exhibit increased GLP-1 secretion and insulin resistance independent of obesity and body weight (Wang et al., 2015; Clegg et al., 2011), and girls with CPP show high serum leptin levels uncorrelated with body mass index (BMI; Zurita-Cruz et al., 2021; Kang et al., 2018).