PCK2 and obesity due to melanocortin 4 receptor deficiency: This is contradictory as Fgf21 expression significantly reduces blood sugar levels and body weights in mice with diet induced obesity by reducing serum triglycerides, reversing hepatic steatosis and suppressing glucose production [27,28], while Pepck expression indicates increased gluconeogenesis, which suggests that the body is resisting the weight loss due to diet reversal and trying to increase glucose production.