Kristal A R, Andrilla C H, Koepsell T D, Diehr P H, Cheadle A
Fred Hutchinson Cancer Research Center, Seattle, WA 98104, USA.
J Am Diet Assoc. 1998 Jan;98(1):40-3. doi: 10.1016/S0002-8223(98)00012-1.
Evaluations of trials of the effectiveness of dietary intervention programs may be compromised by response set biases, such as those attributable to social desirability. Participants who receive a behavioral intervention may bias their reports of diet to appear in compliance with intervention goals. This study examined whether responses to standard dietary assessment instruments could be affected by a brief dietary intervention.
We assigned 192 undergraduate students randomly to (a) see a 17-minute videotape on the consequences of eating a high-fat diet or a placebo videotape on workplace management and (b) receive preintervention and post-intervention assessments or only postintervention assessment. Dietary assessments included 4 independent measures of fat intake.
Among women, bias (intervention minus control) was -9.7 g fat (from a short food frequency questionnaire) and -0.6 high-fat foods (from a questionnaire about use of 23 foods in the previous day) (P < .05 for both). No results were significant among men or for 2 instruments that measured more qualitative aspects of fat-related dietary habits.
Even a modest dietary intervention can affect responses to dietary assessment instruments. Nutritionists should recognize that assessment of adherence to dietary change recommendations, when based on dietary self-report, can be overestimated as a result of response set biases.
饮食干预项目有效性试验的评估可能会受到反应定势偏差的影响，比如那些归因于社会期望的偏差。接受行为干预的参与者可能会使他们的饮食报告出现偏差，以显示符合干预目标。本研究调查了简短的饮食干预是否会影响对标准饮食评估工具的回答。
我们将192名本科生随机分为两组：（a）观看一段17分钟关于高脂饮食后果的录像带或一段关于职场管理的安慰剂录像带；（b）接受干预前和干预后的评估，或仅接受干预后的评估。饮食评估包括4项独立的脂肪摄入量测量指标。
在女性中，偏差（干预组减去对照组）为-9.7克脂肪（来自简短食物频率问卷）和-0.6份高脂食物（来自前一天23种食物食用情况问卷）（两者P值均<0.05）。在男性中，以及对于另外2项测量与脂肪相关饮食习惯更多定性方面的工具，均未得出显著结果。
即使是适度的饮食干预也会影响对饮食评估工具的回答。营养学家应该认识到，基于饮食自我报告来评估对饮食改变建议的依从性时，由于反应定势偏差，可能会高估结果。
