Accuracy Of Portion Size Estimates Research Articles

The Accuracy of Portion Size Reporting on Self-Administered Online 24-Hour Dietary Recalls Among Women With Low Incomes.

Accurately estimating portion sizes remains a challenge in dietary assessment. Digital images used in online 24-hour dietary recalls may be conducive to accuracy. The current analyses were conducted to examine the accuracy of portion size estimation by women with low incomes who completed 24-hour dietary recalls using the online Automated Self-Administered 24-hour Dietary Assessment Tool (ASA24) in the Food and Eating Assessment Study II. True dietary intake was observed for 3 meals on 1 day through a controlled feeding study conducted from May through July 2016. The following day, participants completed an unannounced 24-hour dietary recall using ASA24, independently or with assistance in a small-group setting. Participants included 302 women aged 18 to 82 years living in the Washington, DC, area who met the income thresholds for the Supplemental Nutrition Assistance Program. The accuracy of portion size estimation was assessed by comparing the weight truly consumed (observed) and the weight reported for predetermined categories of foods and beverages. The differences between observed and reported portions were examined and linear regression tested differences by recall condition. Analyses were conducted by condition and repeated with stratification by racial/ethnic identity, education, and body mass index. On average across foods and beverages, reported portion sizes were 7.4 g (95% CI, 4.3-10.5) and 6.4 g (95% CI, 2.8-10.0) higher than observed portion sizes in the independent and assisted conditions, respectively. Portion sizes were overestimated for small pieces and shaped foods in both conditions, as well as for amorphous/soft foods in the assisted condition and underestimated for single-unit foods in both conditions. Misestimation was fairly consistent by participants' race/ethnicity, education, and body mass index, to varying magnitudes. Women with low incomes overestimated the amounts of foods and beverages consumed across several categories using online 24-hour dietary recalls with digital images to support portion size estimation. Assistance with ASA24 had little impact on accuracy.

Effect of Gradually Reduced Portion Size Estimation Training on Portion Size and Daily Energy Intake Estimation Accuracy

ObjectivesWe examined the effect of gradually reduced guidance and feedback on portion size and daily reported energy intake (EI) estimation accuracy. We hypothesized that training would result in relatively accurate portion size estimation at a group level and that portion sizes would be most accurately estimated for solid foods compared with amorphous and liquid foods. We also expected that those who performed better in portion size testing to more accurately report EI.MethodsIn a single session, healthy, nonsmoking participants (n = 29; 38% F; aged 23.0 ± 4.8 y; BMI 22.7 ± 3.2 kg/m2 (mean ± SD)) were given training and gradually reduced written and oral guidance for portion size estimation over three training meals (meals 1–3) followed by one test meal. No instruction was provided for the test meal (meal 4), but oral feedback was provided afterwards. The meals used typical American foods and consisted of food replicas supplemented with real condiments and beverages. The next day, participants were invited to eat breakfast, lunch, and dinner at the university food court. Food selection was unrestricted and all foods and beverages chosen by participants were weighed by researchers who completed a weighed food intake record. After consuming each meal, participants recorded their food intake from the food court using a web-based food diary (ASA24 in record mode). EI from the food diary was calculated and compared with EI from the weighed food record.ResultsRepeated measures ANOVA showed that portion size estimation tended to worsen with meal progression, with meals 4 and 2 being significantly underestimated by −4.5 ± 31.2 and −38.9 ± 120.5 g, respectively, versus 17.4 ± 18.0 g overestimation in meal 1 (p < 0.05). The percentage of foods correctly estimated was higher with solids (83.7%) and liquids (87.1%) compared with amorphous foods (75.3%). Correlations between portion size estimation accuracy and daily EI estimation accuracy were not significant (r = 0.18; p = 0.37).ConclusionsThese results suggest that gradually reduced guidance may not be useful for portion size estimation. Alternatively, participants may not have been familiar with the foods used in the test and training meals, or practice on a greater number of meals containing a broader array of foods may be needed.Funding SourcesNIDDK.

The accuracy of portion size estimation using food images and textual descriptions of portion sizes: an evaluation study.

BackgroundInaccurate self‐report of portion sizes is a major cause of measurement error in dietary assessment. To reduce this error, different portion size estimation aids (PSEAs) have been developed, including food images (image based, IB‐PSE) and textual descriptions of portion sizes (text‐based, TB‐PSE). We assessed the accuracy of portion size estimation by IB‐PSE and TB‐PSE.MethodsTrue intake of one lunch was ascertained in forty participants. Self‐reported portion sizes were assessed after 2 and 24 hours by means of TB‐PSE and IB‐PSE, in random order. Wilcoxon's tests were used to compare mean true intakes to reported intakes. Moreover, proportions of reported portion sizes within 10% and 25% of true intake were assessed. An adapted Bland‐Altman approach was used to assess agreement between true and reported portion sizes. Analyses were conducted for all foods and drinks combined and for predetermined food types.ResultsNo significant differences were observed between reported portion sizes at 2 and 24 hours after lunch. Combining median relative errors of all foods items resulted in an overall 0% error rate for TB‐PSE and 6% error rate for IB‐PSE. Comparing reported portion sizes within 10% (31% vs. 13%) and 25% (50% vs. 35%) of the true intake showed a better performance for TB‐PSE compared to IP‐PSE, respectively. Bland‐Altman plots indicated a higher agreement between reported and true intake for TB‐PSE compared to IB‐PSE.ConclusionsAlthough the use of TB‐PSE still results in measurement error, our results suggest a more accurate dietary intake assessment with TB‐PSE than IB‐PSE.

A Systematic Review of Sensor-Based Methodologies for Food Portion Size Estimation

Food portion size estimation (FPSE) is critical in dietary assessment and energy intake estimation. Traditional methods such as visual estimation are now replaced by faster, more accurate sensor-based methods. This article presents a comprehensive review of the use of sensor methodologies for portion size estimation. The review was conducted using the PRISMA guidelines and full texts of 67 scientific articles were reviewed. The contributions of this article are three-fold: i) A taxonomy for sensor-based (SB) FPSE methods was identified, classifying the sensors (as wearable, portable and stationary) and the methodology (as direct and indirect). ii) A novel comprehensive review of the state-of-the-art SB-FPSE methods was conducted and 5 sensor modalities (Acoustic, Strain, Imaging, Weighing, and Motion sensors) were identified. iii) The accuracy of portion size estimation and the applicability to free-living conditions of these SB-FPSE methods were assessed. This article concludes with a discussion of challenges and future trends of SB-FPSE.

Accuracy of portion size estimation by canteen and school staff on school meals

Abstract Background A correct estimation of food portions is essential for canteen and school staff involved on school meals, affecting children's nutritional status. Thus, it is essential evaluate food portions perception, aiming to improve benefits provided by school meals. Methods This study focused on 35 Portuguese public schools of the city of Porto, that daily offer 6500 lunches to children aged 3 to 10 years old. At each school, the food handler responsible for platting at canteen and a school staff member responsible for the daily supervising of school meals was included. In line service, a meal composed by protein component, side dish, vegetables, bread and fruit was randomly selected. Participants estimated food portion sizes in grams by observing portions of each meal component, posteriorly weighed using a digital scale. Estimation and real values were compared for both participants. Results A total of 175 meal components were evaluated by 70 observers. Canteen staff underestimated, on average, 36.9g of side dish (p = 0.010), 63.7g of fruit (p &amp;lt; 0.001) and 16.2g of bread (p &amp;lt; 0.001). School staff underestimated, on average, 42.1g of side dish (p = 0.043), 70.7g of fruit (p &amp;lt; 0.001) and 24.1 of bread (p &amp;lt; 0.001). Dish type influenced the portion estimation by school staff with regard to the side dish (p = 0.026), being visual estimate of composed dishes closer to real values compared to non-composed dishes. Canteen staff attend to in-situ kitchen better estimated the portions of fruit and bread. Conclusions Food portions of side dish, bread and fruit were underestimated, so it can be concluded that the visual perception of canteen and school staff on school lunch is not accurate. It is essential training to ensure adequate portions serving in school meals and promoting actions for school staff to avoid the encouragement of overconsumption by children. These actions could have a great public health impact either on nutritional status adequacy and on food waste reduction. Key messages Food portions estimation of canteen staff was closer to real portion compared with school staff. It is huge the difficulty in visually estimation of food portions on school meals.

The Development and Validation of Food Atlas for Portion Size Estimation in the Balkan Region.

Assessment of portion sizes is an important factor for the accuracy of food consumption surveys. The objective of this study was to develop and validate a food atlas of commonly consumed foods in the Balkan region in order to improve the accuracy of portion size estimation for food consumption surveys. A list of 135 foods and their portion sizes was based on previously conducted food consumption surveys in this region. Food was cooked, measured and served in three or four portion sizes right before being photographed. A validation study was conducted through the visual perception method. Without receiving training on usage of the food picture book, participants were asked to evaluate two portion sizes of 20 selected foods by comparison with a photo series of each food. Portion sizes were evaluated by 18 nutrition professionals and 17 lay individuals who had no nutritional education. Mean differences and the standard deviations of the mean differences (SD) between the portions estimated by each participant and the served portion were calculated. The percentages of participants who selected the correct, adjacent or distant portion size also were calculated. The number of food items that were quantified within the predefined acceptable range (i.e., mean difference < ∣ 0·7 ∣ and SD < 1) was 16 (80%) among lay individuals and 17 (85%) among nutritional professionals. Among 16 photo series that were assessed as “acceptable,” the percentage of all participants, who selected the correct picture, was between 44.3 and 82.9%, with an average of 60.2%. Only three foods were assessed correctly by <50% participants. The percentage of participants who selected the correct or adjacent serving size was above 98% for both lay and professional evaluators. This is the first food atlas containing representative foods and recipes commonly consumed in the Balkan region. However, further adjustments of the methodology should include larger number of food items to be tested, involvement of more participants and provision of training for the users of the food atlas. This food atlas could be used in food consumption surveys in the Balkan region after further testing and validation.

Accuracy of Parental Reporting of Preschoolers' Dietary Intake Using an Online Self-Administered 24-h Recall.

Parents are typically relied upon to report young children’s dietary intake. However, there has been limited research assessing the accuracy of such reports captured using novel dietary assessment tools. The purpose of the current study was to assess the validity of the web-based Automated Self-Administered 24-h Dietary Assessment Tool (ASA24-Canada) for capturing dietary intake among children aged two-five years (n = 40), using parental proxy reporting. The study was conducted in a daycare setting, allowing for standardization of foods and drinks offered and direct observation of intake. Parental-reported intake was compared to true intake for lunch and dinner, as well as an afternoon snack, on a single day. Each eating occasion, including plate waste, was unobtrusively documented. Parents were not present for lunch or the afternoon snack, but joined their children at the daycare centre for the dinner meal. The following day, parents reported their children’s intake from the previous 24-h period using ASA24-Canada. For the eating occasions assessed, parents reported exact or close matches for 79.2% (82.3% for lunch, 81.2% for the snack, and 77.4% for dinner) of the foods and beverages truly consumed by children. Estimates of intake for energy and macronutrients examined (carbohydrates, fat, and protein) based on parental reports were higher than those based on true (observed) intake. Our findings suggest that parents are able to report what their preschool children eat and drink relatively accurately. However, the accuracy of portion size estimates is low. Strategies to enhance portion size reporting are needed to improve parental proxy reporting.

Feasibility of Reviewing Digital Food Images for Dietary Assessment among Nutrition Professionals.

Validity of image-assisted and image-based dietary assessment methods relies on the accuracy of portion size estimation based on food images. However, little is known on the ability of nutrition professionals in assessing dietary intake based on digital food images. This study aims to examine the ability of nutrition professionals in reviewing food images with regard to food item identification and portion size estimation. Thirty-eight nutritionists, dietitians, and nutrition researchers participated in this study. Through an online questionnaire, participants’ accuracy in identifying food items and estimating portion sizes of two sets of digital food images presenting a meal on a plate (Image PL) and in a bowl (Image BW) were tested. Participants reported higher accuracy in interpreting Image BW compared to Image PL, both in terms of accuracy in food identification (75.3 ± 17.6 vs. 68.9 ± 17.1%) and percentage difference in portion size estimation (44.3 ± 16.6 vs. 47.6 ± 21.2%). Weight of raw vegetables was significantly underestimated (−45.1 ± 22.8% vs. −21.2 ± 37.4%), while drink was significantly overestimated (40.1 ± 45.8% vs. 26.1 ± 32.2) in both images. Less than one-third of the participants estimated portion size within 10% of actual weight for Image PL (23.7%) and Image BW (32.3%). Accuracy of nutrition professionals in reviewing food images could be further improved with training on better perception of portion sizes from images.

Food photographs in portion size estimation among adolescent Mozambican girls.

To assess the validity of food photographs in portion size estimation among adolescent girls in Mozambique. The study was carried out in preparation for the larger ZANE study, which used the 24 h dietary recall method. Life-sized photographs of three portion sizes of two staple foods and three sauces were produced. Participants ate weighed portions of one staple food and one sauce. After the meal, they were asked to estimate the amount of food with the aid of the food photographs. Zambezia Province, Mozambique. Ninety-nine girls aged 13–18 years. The mean differences between estimated and actual portion sizes relative to the actual portion size ranged from 219% to 8% for different foods. The respective mean difference for all foods combined was 25% (95% CI 212, 2 %). Especially larger portions of the staple foods were often underestimated. For the staple foods, between 62% and 64% of the participants were classified into the same thirds of the distribution of estimated and actual food consumption and for sauces, the percentages ranged from 38% to 63%. Bland–Altman plots showed wide limits of agreement. Using life-sized food photographs among adolescent Mozambican girls resulted in a rather large variation in the accuracy of individuals’ estimates. The ability to rank individuals according to their consumption was, however, satisfactory for most foods. There seems to be a need to further develop and test food photographs used in different populations in Sub-Saharan Africa to improve the accuracy of portion size estimates.

Food Portion Estimation by Children with Obesity: The Effects of Estimation Method and Food Type

Several factors influence children's ability to report accurate information about their dietary intake. To date, one understudied area of dietary assessment research relates to children's ability to estimate portion sizes of food. The purpose of this cross-sectional research was to examine food portion size estimation accuracy in 7- to 18-year-old children with obesity. Two within-subject experiments (Experiment 1: n=28, Experiment 2: n=27) were conducted in Edmonton, Alberta, Canada, during 2007-2008. Three types of portion size measurement aids (PSMAs) (eg, measuring cups and spoons, household objects [full and half-sized], and modeling clay) were counterbalanced in a Latin Square design for participants to estimate four types of foods (ie, solid, liquid, amorphous pieces, and amorphous masses). Analyses of variance conducted on percent of signed and absolute errors yielded significant PSMA type×food type interactions (P<0.01) in both experiments. Across all food types, for Experiments 1 and 2, measuring cups and spoons produced the least accurate estimates with respect to absolute error (54.2% and 53.1%, respectively), whereas modeling clay produced the most accurate estimates (40.6% and 33.2%, respectively). Half sizes of household objects also yielded enhanced accuracy (47.9% to 37.2%). Finally, there were significant differences in accuracy between amorphous pieces (eg, grapes) vs amorphous masses (eg, mashed potatoes; P<0.01), indicating that there are qualitative differences in how different amorphous foods are estimated. These data are relevant when collecting food intake data from children with obesity and indicate that different PSMAs may be needed to optimize food portion size estimation accuracy for different food types.

Children’s accuracy of portion size estimation using digital food images: effects of interface design and size of image on computer screen

To test the effect of image size and presence of size cues on the accuracy of portion size estimation by children. Children were randomly assigned to seeing images with or without food size cues (utensils and checked tablecloth) and were presented with sixteen food models (foods commonly eaten by children) in varying portion sizes, one at a time. They estimated each food model's portion size by selecting a digital food image. The same food images were presented in two ways: (i) as small, graduated portion size images all on one screen or (ii) by scrolling across large, graduated portion size images, one per sequential screen. Laboratory-based with computer and food models. Volunteer multi-ethnic sample of 120 children, equally distributed by gender and ages (8 to 13 years) in 2008-2009. Average percentage of correctly classified foods was 60·3 %. There were no differences in accuracy by any design factor or demographic characteristic. Multiple small pictures on the screen at once took half the time to estimate portion size compared with scrolling through large pictures. Larger pictures had more overestimation of size. Multiple images of successively larger portion sizes of a food on one computer screen facilitated quicker portion size responses with no decrease in accuracy. This is the method of choice for portion size estimation on a computer.

A New Portion Size Estimation Aid for Wedge-Shaped Foods

Dietary surveys are important for understanding food consumption patterns in national studies, clinical research, and patient counseling. Portion size estimation aids usually increase accuracy of consumers’ reports of the amount of food they ate in dietary surveys. However, wedge-shaped foods (eg, pie, cake, and pizza) pose special problems; this shape is not easily estimated by previously available portion size estimation aids. In focus groups, respondents indicate they need a portion size estimation aid that is easier to use than a ruler for portion estimation of wedge-shaped foods. An adjustable wedge was developed and tested with 320 respondents, ages 18 to 65 years, of various races and education levels, and both sexes, in four states using multiple sizes and types of wedge-shaped foods. The accuracy of portion size estimation with the two portion size estimation aids was assessed. The adjustable wedge gave similar results to the ruler for most portions tested, but was more accurate ( P<0.05) than the ruler in approximately one third of comparisons. Both aids resulted in substantial misestimation, indicating that regardless of aid some people have difficulty estimating portions of wedge-shaped foods. The adjustable wedge was easy for people to use and can be recommended as an option for estimating portion size of wedge-shaped foods.

Accuracy of estimates of food portion size using food photographs – the importance of using age-appropriate tools

In order to obtain a measure of nutrient intake, a measure or estimate of the amount of food consumed is required. Weighing foods imposes a large burden on subjects, often resulting in underreporting. Tools are available to assist subjects in providing an estimate of portion size and these include food photographs. The application of these tools in improving portion size estimation by children has not been investigated systematically. To assess the accuracy with which children are able to estimate food portion sizes using food photographs designed for use with adults, and to determine whether the accuracy of estimates is improved when age-appropriate portion size photographs are provided. Original data from three separate studies, on the accuracy of portion size estimates by adults using food photographs, by children using adult photographs and by children using age-appropriate photographs, are analysed and compared. One hundred and thirty-five adults aged 18 to 90 years and 210 children aged 4 to 11 years. Children's estimates of portion sizes using age-appropriate food photographs were significantly more accurate (an underestimate of 1% on average) than estimates using photographs designed for use with adults (an overestimate of 45% on average). Accuracy of children's estimates of portion size using age-appropriate photographs was not significantly different from that of adults. Children overestimated a food's weight by 18% on average and adults underestimated by 5%. Providing children with food photographs depicting age-appropriate portion sizes greatly increases the accuracy of portion size estimates compared with estimates using photographs designed for use with adults.

Portion size estimation and expectation of accuracy

The accuracy of portion size estimates is critical in dietary assessment. The objectives of this study were to determine the magnitude and direction of error in estimating food amounts using computer-based portion anchors; to compare errors between use of computer- and poster-displayed anchors; and to assess level of accuracy that can reasonably be expected for different food types. A total of 101 subjects estimated amounts of food items (five solid, four amorphous, three liquid) using computer-based portion anchors. Half of the subjects also estimated five of the foods using digital photographs printed onto a poster. Two modes of testing were conducted: real time, in which foods were displayed near the computer or poster, and short-term recall, in which food was consumed and then estimated. Overall error (mean± se) in real time was 4.8%±1.8%; by food type, solid was 8.3%±2.3%, amorphous was −10%±2.7%, and liquid was 19%±5%. However, group mean values could mask true errors. This research showed that even within food type, variables including amount served and its closeness to anchor size affected accuracy of estimates. For each food, amount served correlated inversely with magnitude of error. The findings provide insight into sources of error in portion estimation, and factors to consider in setting reasonable levels of accuracy.

Intense Practice Enhances Accuracy of Portion Size Estimation of Amorphous Foods

Intense Practice Enhances Accuracy of Portion Size Estimation of Amorphous Foods