title: Assessment of the accuracy of portion size reports using computer-based food photographs aids in the development of an automated self-administered 24-hour recall.
abstract: OBJECTIVE
  To assess the accuracy of portion-size estimates and participant preferences using various presentations of digital images.
  
  
  METHODS
  Two observational feeding studies were conducted. In both, each participant selected and consumed foods for breakfast and lunch, buffet style, serving themselves portions of nine foods representing five forms (eg, amorphous, pieces). Serving containers were weighed unobtrusively before and after selection as was plate waste. The next day, participants used a computer software program to select photographs representing portion sizes of foods consumed the previous day. Preference information was also collected. In Study 1 (n=29), participants were presented with four different types of images (aerial photographs, angled photographs, images of mounds, and household measures) and two types of screen presentations (simultaneous images vs an empty plate that filled with images of food portions when clicked). In Study 2 (n=20), images were presented in two ways that varied by size (large vs small) and number (4 vs 8).
  
  
  METHODS
  Convenience sample of volunteers of varying background in an office setting.
  
  
  METHODS
  Repeated-measures analysis of variance of absolute differences between actual and reported portions sizes by presentation methods.
  
  
  RESULTS
  Accuracy results were largely not statistically significant, indicating that no one image type was most accurate. Accuracy results indicated the use of eight vs four images was more accurate. Strong participant preferences supported presenting simultaneous vs sequential images.
  
  
  CONCLUSIONS
  These findings support the use of aerial photographs in the automated self-administered 24-hour recall. For some food forms, images of mounds or household measures are as accurate as images of food and, therefore, are a cost-effective alternative to photographs of foods.
authors.affiliation: National Cancer Institute, Division of Cancer Control and Population Sciences, Applied Research Program, Risk Factor Monitoring and Methods Branch, Bethesda, MD 20892-7344, USA. subara@mail.nih.gov
authors.forename: Amy F
authors.initials: AF
authors.lastname: Subar
authors.forename: Jennifer
authors.initials: J
authors.lastname: Crafts
authors.forename: Thea Palmer
authors.initials: TP
authors.lastname: Zimmerman
authors.forename: Michael
authors.initials: M
authors.lastname: Wilson
authors.forename: Beth
authors.initials: B
authors.lastname: Mittl
authors.forename: Noemi G
authors.initials: NG
authors.lastname: Islam
authors.forename: Suzanne
authors.initials: S
authors.lastname: McNutt
authors.forename: Nancy
authors.initials: N
authors.lastname: Potischman
authors.forename: Richard
authors.initials: R
authors.lastname: Buday
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Hull
authors.forename: Tom
authors.initials: T
authors.lastname: Baranowski
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Guenther
authors.forename: Gordon
authors.initials: G
authors.lastname: Willis
authors.forename: Ramsey
authors.initials: R
authors.lastname: Tapia
authors.forename: Frances E
authors.initials: FE
authors.lastname: Thompson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D004034:Diet Surveys; D004522:Educational Status; D002149:Energy Intake / Q000502:physiology; D005260:Female; D005502:Food / Q000145:classification* / Q000592:standards; D005518:Food Preferences; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation / Q000379:methods / Q000592:standards*; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D015596:Nutrition Assessment; D010781:Photography / Q000592:standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012858:Size Perception; D055815:Young Adult