MC4R and Obesity: In control individuals with obesity, the decrease in medium-chain and long-chain fatty acids from 60 min was followed by the accumulation of fatty acids and glycerol to form monoglycerols and diacylglycerols; the accumulation of monoglycerols and diacylglycerols was attenuated in MC4R deficiency (Fig. 4d and Supplementary Table 15).