National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Phoenix, AZ, USA.
Am J Clin Nutr. 2010 Feb;91(2):343-8. doi: 10.3945/ajcn.2009.28315. Epub 2009 Nov 18.
Accurate assessment of energy intake is difficult but critical for the evaluation of eating behavior and intervention effects. Consequently, methods to assess ad libitum energy intake under controlled conditions have been developed.
Our objective was to evaluate the reproducibility of ad libitum energy intake with the use of a computerized vending machine system.
Twelve individuals (mean + or - SD: 36 + or - 8 y old; 41 + or - 8% body fat) consumed a weight-maintaining diet for 3 d; subsequently, they self-selected all food with the use of a computerized vending machine system for an additional 3 d. Mean daily energy intake was calculated from the actual weight of foods consumed and expressed as a percentage of weight-maintenance energy needs (%WMEN). Subjects repeated the study multiple times during 2 y. The within-person reproducibility of energy intake was determined through the calculation of the intraclass correlation coefficients (ICCs) between visits.
Daily energy intake for all subjects was 5020 + or - 1753 kcal during visit 1 and 4855 + or - 1615 kcal during visit 2. There were no significant associations between energy intake and body weight, body mass index, or percentage body fat while subjects used the vending machines, which indicates that intake was not driven by body size or need. Despite overconsumption (%WMEN = 181 + or - 57%), the reproducibility of intake between visits, whether expressed as daily energy intake (ICC = 0.90), %WMEN (ICC = 0.86), weight of food consumed (ICC = 0.87), or fat intake (g/d; ICC = 0.87), was highly significant (P < 0.0001).
Although ad libitum energy intake exceeded %WMEN, the within-person reliability of this intake across multiple visits was high, which makes this a reproducible method for the measurement of ad libitum intake in subjects who reside in a research unit. This trial was registered at clinicaltrials.gov as NCT00342732.
准确评估能量摄入是评估饮食行为和干预效果的关键，但却很难做到。因此，人们开发了在受控条件下评估随意能量摄入的方法。
我们的目的是评估使用计算机自动售货机系统评估随意能量摄入的再现性。
12 名个体（平均+或-标准差：36+或-8 岁；41+或-8%体脂）连续 3 天摄入维持体重的饮食；随后，他们使用计算机自动售货机系统自行选择所有食物。通过消耗食物的实际重量计算平均每日能量摄入量，并表示为维持体重能量需求的百分比（%WMEN）。受试者在 2 年内多次重复该研究。通过计算两次就诊之间的组内相关系数（ICC）来确定能量摄入的个体内再现性。
所有受试者在第 1 次就诊时的日能量摄入量为 5020+或-1753 kcal，在第 2 次就诊时为 4855+或-1615 kcal。当受试者使用自动售货机时，能量摄入与体重、体重指数或体脂百分比之间没有显著关联，这表明摄入不受身体大小或需求的影响。尽管存在过度摄入（%WMEN=181+或-57%），但在两次就诊之间，摄入的再现性，无论是以每日能量摄入（ICC=0.90）、%WMEN（ICC=0.86）、消耗的食物重量（ICC=0.87）还是脂肪摄入量（g/d；ICC=0.87）表示，均具有高度显著性（P<0.0001）。
尽管随意能量摄入超过了%WMEN，但在多个就诊期间，这种摄入的个体内可靠性很高，这使得该方法在居住在研究单位的受试者中测量随意摄入具有可重复性。本试验在 clinicaltrials.gov 注册，编号为 NCT00342732。
