Some people often wonder whether they are fighting a battle with their genes to maintain a healthy weight. In fact, researchers have provided plenty of evidence that people are born with tendencies to be lighter or heavier. For example, studies of identical twins have revealed great similarity in their overall weight. Part of this similarity may be explained by the finding that some people are born to burn a lot of calories just through ordinary day-to-day activities while others are not. Those who are not are more at risk for weight gain.
Researchers have discovered some of the actual genetic mechanisms (机制) that may make some individuals more likely to be obese. For example, a gene has been found that appears to control signals to the brain that enough fat has been stored in the body in the course of a meal—so the individual should stop eating. The gene influences the production of leptin (瘦蛋白), which keeps appetite under control. If leptin doesn't work well, it is likely that individuals will continue to eat. Thus the gene that controls leptin appears to have a critical influence on the potential for obesity.
The confirmation that leptin plays a role in weight control has encouraged researchers to identify and understand other weight-related genes. Recent attention has focused on a gene called GAD2. GAD2 helps control the amount of the neurotransmitter (神经递质) GABA. In general, when more GABA is available, appetite is increased. For that reason, people who have a form of GAD2 that allows more GABA to be available may be at risk for overeating. You can see that GAD2 is not directly an obesity gene. Rather it has an indirect influence on obesity through its direct influence on GABA.
Genetic research holds out the promise of innovative solutions to obesity. Researchers hope that an understanding of the link between genus and weight control will enable them to provide new drug treatments. Nonetheless, even the most optimistic researchers provide a warning: "Innovative drugs will be effective only when they are used along with lifestyle changes."
