Scientists have discovered one likely reason some people eat to live and others live to eat.

Researchers at the University at Buffalo in New York have found that people with genetically lower dopamine – a neurotransmitter that helps make activities and substances more rewarding – find food to be more rewarding than people without it. In other words, they are more motivated to eat, and they eat more.

The findings, which appear in Behavioral Neuroscience, offer insights that could inspire treatment programmes for obesity, and maybe even genetically targeted drugs.

Researchers measured the body mass of 29 obese adults and 45 who were not obese. They also swabbed DNA samples from inside their cheeks, had them fill in eating questionnaires and had them perform a series of tasks.

Both obesity and the genetic make-up associated with fewer dopamine receptors predicted a significant response to food's rewarding power. Participants for whom food was most rewarding consumed more calories. What is more, obese participants clearly found food to be more rewarding than non-obese participants.

为什么有些人吃东西是为了活着，而另一些人活着是为了吃？科学家们发现了一个可能的原因。

纽约州立大学水牛城分校(University at Buffalo in New York)的研究人员发现，与其他人相比，由于遗传因素导致体内多巴胺含量较低的人觉得食物更令人满足。换句话说，他们吃东西的动力更足，吃的也更多。多巴胺是一种神经递质，能让某些行为或物质给人们带来更大的满足感。

这些研究结果刊登在《行为神经科学》(Behavioral Neuroscience)期刊上，由此提出的见解可能会为肥胖症治疗项目带来启发，甚至可能为基因药物提供灵感。

研究人员测量了29名肥胖成年人与45名不肥胖的成年人的体重，还用棉签从他们的脸颊内侧擦取了DNA样本，让他们填写关于吃东西的调查问卷，并让他们完成一系列任务。

肥胖和与多巴胺受体较少相关的基因构造，都预示着对食物令人满足的力量做出强烈回应。认为食物最令人满意的参与者摄取的卡路里更多。此外，与不肥胖的参与者相比，肥胖参与者显然认为食物更能带来满足感。