A City Guide To Harbin for . Obese individuals inherit lower metabolic rates. However, obese people are not consistently found to have lower metabolic rates than comparable thin persons. . Obese individuals may have deficiencies in a hormone responsible for appetite control, or lack of control. This last explanation has received attention since the s, when a gene mutation was identified in some laboratory mice that had become highly obese Coleman Subsequent cloning of this mutated gene found that it was only expressed in fat cells and that it encoded a protein hormone called leptin Zhang et al Leptin levels are positively correlated with fat deposits in humans; low levels of injected leptin have been found to reduce eating behaviour and thus body fat in obese mice. This appears to happen due to leptin-signalling receptors in the hypothalamus, which controls functions such as eating see Chapter However, Pinel describes how research has not found similar genetic mutation in all obese humans and how H – R I S K injected leptin has not consistently reduced body fat in the obese. A City Guide To Harbin 2016.