FABP4 and morbid obesity: Low-density lipoprotein receptor (LDLR) is regulated by the circadian clock via the complex Clock/Bmal1 (45) In addition, fatty acid binding protein 4 (FABP4,) one of the main lipid-binding proteins in adipose tissue and liver, has been shown to have a circadian expression in both tissues (46) and it is overexpressed in the liver in the contexts of morbid obesity and insulin resistance (47).