CLOCK and obesity due to melanocortin 4 receptor deficiency: Furthermore, a recent study observed that BMAL1 overexpression can enhance circadian clock function and β cell function, thus enhancing GSIS and systemic glucose metabolism in the context of diet-induced obesity.48 In short, the above-mentioned findings could imply that BMAL1 gene polymorphisms and nutritional status have an essential role in affecting fasting blood glucose levels in children.