Dietary assessment instruments are susceptible to intervention-associated response set bias

J Am Diet Assoc. 1998 Jan;98(1):40-3. doi: 10.1016/S0002-8223(98)00012-1.


Objective: 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.

Design: 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.

Results: 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.

Applications: 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.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Adult
  • Bias
  • Dietary Fats / administration & dosage*
  • Feeding Behavior / psychology*
  • Female
  • Humans
  • Male
  • Social Desirability
  • Surveys and Questionnaires
  • Videotape Recording


  • Dietary Fats