Are you obese¹? Well, blame it on your social nature.

Outgoing people tend to be overweight, while anxious types are more likely to be thin, according to Japanese researchers who examined the links between personality and body mass index.

More than 30,000 people in northeastern Japan aged between 40 and 64 were quizzed about their height and weight, and given a personality test, according to a study published in the Journal of Psychosomatic Research.

The results showed that outgoing people were far more likely than other people to have a body mass index (BMI) of more than 25, a WHO definition of overweight, said Masako Kakizaki of Tohoku University, who led the analysis.

After controlling for other factors, such as smoking, men in the most extrovert² category were 1.73 times more likely to be obese than their most introvert³ counterparts. Extrovert women were 1.53 times as likely to be obese.

People ranked as having the most anxious personalities⁴ were twice as likely as the least anxious to be underweight, or have a BMI of less than 18.5, the study found.

"These results may provide clues to devising more effective measures for preventing overweight, obesity⁵ or underweight," the researchers said in their paper.

觉得自己太胖？那就要怪你天生外向的性格了。

日本研究人员对人的性格与体重指数之间的关系进行了探究，并发现性格外向的人容易肥胖，而焦虑不安的人则易瘦。

身心健康研究》期刊中的一篇论文称，研究人员对日本东北部地区3万多名年龄在40岁至64岁之间受访者的身高和体重进行了调查，并对他们进行了性格测试。

据研究负责人、日本东北大学的Masako Kakizaki介绍，研究结果表明，性格外向的人体重指数大于25的几率远远高于其他性格类型的人。根据世界卫生组织的标准，体重指数大于25即为“超重”。

在排除抽烟等其它因素的影响后，研究人员发现，最外向型男性肥胖的几率为最内向型的1.73倍，最外向女性肥胖的几率为最内向女性的1.53倍。

研究发现，最易焦虑的人体重不达标的可能性更大，其体重指数小于18.5的几率为性格不焦虑型的两倍。

研究人员在研究论文中提到：“研究结果也许能为找到更有效预防体重超标、肥胖或体重不足的办法提供线索。”