Validity of a Digital Diet Estimation Method for Use with Preschool Children.

BACKGROUND: The validity of using the Remote Food Photography Method (RFPM) for measuring food intake of minority preschool children's intake is not well documented. OBJECTIVE: Our aim was to determine the validity of intake estimations made by human raters using the RFPM compared with those obtained by weighing all foods and beverages consumed by 3- to 5-year-old children (weighed method). DESIGN: We conducted a cross-sectional observational study. PARTICIPANTS/SETTINGS: A convenience sample of 54 3- to 5-year-old Hispanic and African-American children were observed during a 12-hour period at Baylor Metabolic Research Unit between June 2013 and January 2014. MAIN OUTCOME MEASURES: All foods/beverages consumed by the children were provided by Baylor research coordinators who took and wirelessly transmitted before-and-after pictures of the trays to trained human raters at the Pennington Biomedical Research Center who estimated grams consumed. Energy and macronutrients were calculated using the Food and Nutrient Database for Dietary Studies or food facts data provided by manufacturers. STATISTICAL ANALYSES: Paired t test, mean differences, and Bland-Altman limits of agreement were performed. RESULTS: Compared to the weighed method, the rater method significantly overestimated total intake by 34±71 g (P<0.0001), with a mean percent error of 2.9% (root mean square error=7.1%), and total energy intake by 75±102 kcal (P<0.0001), with a mean percent error of 7.5% (root mean square error=12.3%). The standard error for the macronutrient intakes ranged from 11.0% to 20.2%. The Bland-Altman approach demonstrated a positive slope for the rater method relative to the weighed method for total intake in grams (P=0.006), carbohydrate (P=0.01), and protein (P=0.01) (ie, magnitude of the bias increased with increasing intakes). CONCLUSIONS: The rater method overestimated total intake in grams and energy in kilocalories in minority preschool children in a well-controlled condition and needs to be further tested in a free-living environment.

Validity of the Remote Food Photography Method Against Doubly Labeled Water Among Minority Preschoolers.

OBJECTIVE: The aim of this study was to determine the validity of energy intake (EI) estimations made using the remote food photography method (RFPM) compared to the doubly labeled water (DLW) method in minority preschool children in a free-living environment. METHODS: Seven days of food intake and spot urine samples excluding first void collections for DLW analysis were obtained on thirty-nine 3- to 5-year-old Hispanic and African American children. Using an iPhone, caregivers captured before and after pictures of each child's intake, pictures were wirelessly transmitted to trained raters who estimated portion size using existing visual estimation procedures, and energy and macronutrients were calculated. Paired t tests, mean differences, and Bland-Altman limits of agreement were performed. RESULTS: The mean EI was 1,191 ± 256 kcal/d using the RFPM and 1,412 ± 220 kcal/d using the DLW method, resulting in a mean underestimate of 222 kcal/d (-15.6%; P < 0.0001) that was consistent regardless of intake. The RFPM underestimated EI by -28.5% in 34 children and overestimated EI by 15.6% in 5 children. CONCLUSIONS: The RFPM underestimated total EI when compared to the DLW method among preschoolers. Further refinement of the RFPM is needed for assessing the EI of young children.

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.

OBJECTIVE: To assess the accuracy of portion-size estimates and participant preferences using various presentations of digital images. DESIGN: 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). SUBJECTS/SETTING: Convenience sample of volunteers of varying background in an office setting. STATISTICAL ANALYSES PERFORMED: 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.