Rao S
Hum Nutr Clin Nutr. 1987 Jan;41(1):71-9.
In the past, variations in the daily intake of an individual maintaining his weight and activity were considered negligible as it was assumed they arose from measurement errors. It was therefore believed that such variation could be eliminated by averaging over an appropriate period. This, however, is not borne out by the experimental data. The present study reports findings based on a longitudinal diet survey conducted on 43 adolescent schoolboys in a village, over a period of 1 year. A diet survey was carried out for 1 week every 3 months. Intake was estimated by recording the weights of all the food items actually consumed during the day by the students and analysing corresponding food samples in the laboratory. Intake data when analysed for the relative contributions of between- and within-subject variation showed that not only intra-individual variation contributes a substantial portion of the total variation but a significant part of it arises from changes in the mean intake from week to week. The daily intakes of a subsample of 5 students were observed for 49 consecutive d to study the short-term nature of the variation. The results obtained confirm those from the long-term study. Additionally there is an indication that daily intakes of an individual are serially correlated.
过去，人们认为维持体重和活动水平的个体每日摄入量的变化可忽略不计，因为假定这些变化源于测量误差。因此，人们相信通过在适当时间段内进行平均可以消除这种变化。然而，实验数据并未证实这一点。本研究报告了基于对一个村庄的43名青春期男学生进行的为期1年的纵向饮食调查的结果。每3个月进行一次为期1周的饮食调查。通过记录学生当天实际食用的所有食物的重量并在实验室分析相应的食物样本，来估计摄入量。对受试者间和受试者内变异的相对贡献进行分析时，摄入量数据显示，不仅个体内变异在总变异中占很大比例，而且其中很大一部分源于每周平均摄入量的变化。对5名学生的子样本的每日摄入量进行了连续49天的观察，以研究这种变化的短期性质。获得的结果证实了长期研究的结果。此外，有迹象表明个体的每日摄入量存在序列相关性。
