本文利用生物电阻抗法对广西京族的体成分进行了测定，初步分析了其体成分形成的原因。研究组于2020年12月在广西壮族自治区东兴市“京族三岛”测定了430例京族成人（男182例，女248例）的16项指标。结果表明，京族男、女性的体质量、总肌肉量、躯干肌肉量、推定骨量、总能量代谢与年龄呈显著负相关。体成分随年龄增长而发生的变化，主要是自然的生理变化和劳动强度下降所致。随着年龄增长，男性的体脂率升高，这主要是躯干脂肪增多造成的。京族男性的体质量、总肌肉量、推定骨量、总能量代谢、水分率、四肢和躯干肌肉量均大于女性，而体脂率、四肢和躯干脂肪率均小于女性。京族男性比女性拥有更大的体质量和更高比例的骨骼肌，这两方面因素再加上劳动强度的差异，可能导致男性肌肉量、骨量、脂肪率等体成分与女性存在差异。总体来看，京族成人身体偏胖，脂肪含量较高，身体含水量基本正常，体成分特征与同为南亚语系或同在沿海地区的其他中国族群并不相似，而相对更接近于中国蒙古族，并且表现在体质量、体脂率、水分率等方面接近。生活环境、社会经济、日常饮食和劳动强度等因素是导致京族成人体质量及体脂率较高的原因。

In this paper, the bioelectrical impedance analysis was used to measure body composition of Jing peoples in Guangxi. In December 2020, the research team measured 16 indicators of 430 Jing adults (182 males and 248 females) in the “Three Islands of Jing” in Dongxing City, Guangxi Zhuang Autonomous Region. The results show that mass, total body muscle mass, trunk muscle mass, estimated bone mass and total energy metabolism of Jing males and females are significantly negatively correlated with age. Changes in body composition with age are mainly caused by natural physiological changes with decreased labor intensity. The percentage body fat of males increases with age, due to increased trunk fat. The mass, total body muscle mass, estimated bone mass, total energy metabolism, percentage body water, and limbs and trunk muscle mass of Jing males are higher than those of females; while percentage of body fat and of limb and trunk fat are lower than those of females. Jing males possess a greater mass and a higher proportion of skeletal muscle in mass than females. These two last factors coupled with differences in labor intensity could result in discrepancies of body compositions of the two genders, including body muscle mass, bone mass and percentage body fat. Generally speaking, Jing adults are obese with high fat content but normal body water content. Their body composition characteristics are not similar to other Chinese ethnic groups of the same Austroasiatic languages or in the same coastal areas, but are relatively closer to those of Mongols in China, where mass, percentage of body fat and of body water are similar. Factors such as living environment, social economy, daily diet and labor intensity are the reasons for the higher mass and percent body fat of the Jing adults.