HCRT and obesity due to melanocortin 4 receptor deficiency: While it is apparent that Hcrt knockout mice do show a reduction in the intake of food (38, 182) it appears that they still go on to develop obesity later on Hara et al. (38), suggesting that it may not only be food-seeking and food-consumption that is being driven by Hcrt activity, but additional processes underlying food-metabolism as well.