Effects of a Web-based food portion training program on food portion estimation

OBJECTIVE: Assess the effects of a prototype computerized food portion tutorial (CFPT). DESIGN: Participants were randomly assigned to estimate portion sizes for selected food items either prior to or following CFPT training (between groups), and those estimating before CFPT training re-estimated portions after training (within groups). SETTING: Research offices. PARTICIPANTS: Seventy-six adult participants without dietary restrictions. INTERVENTION: The CFPT is a Web-based food portion training program that displays varied portions of 23 food items with user-controllable reference objects and viewing angles. MAIN OUTCOME MEASURES: Estimated vs. weighed portions of food items selected for a meal. ANALYSIS: Nonparametric tests were performed on estimated vs. weighed portion differences and on accuracy ratios between and within groups. RESULTS: A significant difference was found between conditions, both within and between groups, on the discrepancy between estimated and weighed portions for a number of the food items. Training exposure, however, resulted primarily in a shift from underestimation to overestimation, not more accurate estimation. IMPLICATIONS FOR RESEARCH AND PRACTICE: The CFPT produced a significant impact on food portion estimation but appeared to sensitize participants to underestimation errors, leading to overestimation errors. Computerization of food portion training programs holds promise for providing cost-efficient portion estimation training but requires further development and evaluation before being considered for clinical use.     

A study of the use of a photographic food atlas to estimate served and self-served portion sizes

Background: Although it is generally accepted that a weighed intake is the most valid way of assessing nutrient intake, this is not always the most appropriate method. Photographs have been suggested as a useful aid in assessing portion size when other methods of recording dietary intake are used. Method: Male and female subjects ( n =100) were recruited to assess portion sizes of served amounts of mashed potato or cornflakes using food photographs. A second group of subjects ( n =40) were recruited to assess portion sizes of self-served mashed potato or cornflakes using the same photographs. Results: Estimates varied from −70.6% underestimation to +198.7% overestimation for mashed potato, with less variation for the cornflakes where portions were served.® Where the food was self-served, results ranged from −38% and −64% underestimation to +61% and +88% overestimation for cornflakes and mashed potato, respectively.Correlation coefficients between estimated and actual weights of food showed them to be of statistical significance ( P <0.05). Conclusion: Food photographs are a useful and convenient aid in the estimation of food portion sizes.     

Validation of a Web-Based,Time-Use Application to Assess Children’s School Meal Intakes: My E-Diary for Activities and Lifestyle (MEDAL)

My E-Diary for Activities and Lifestyle (MEDAL), a web-based application, was developed to assess the diets of children. This study examined the validity of school recess meals reported by children on MEDAL, using meal photography as the reference. Recess meals were photographed by trained researchers, and food items and portion sizes of recess meals reported on MEDAL were compared to recess meal photos. Validity was assessed by percentages of match, omission and intrusion for food items and percentages of the match, underestimation and overestimation for portion sizes. The Mann–Whitney test and the Wilcoxon matched-pairs signed-rank test examined if sex, school and day of recording influenced the validity of food item reporting. We found that participants (n = 33, aged 10–11 years) recalled 60.2% of food items consumed at recess accurately (matches); omissions (24.6%) were more common than intrusions (15.2%). Omissions tended to be side dishes, and intrusions tended to be high-calorie items. Sex, school and day of recording did not influence validity. For food portion sizes, 58.3% of items were accurately reported. Overestimations (33.3%) were more common than underestimations (8.3%). In conclusion, these children were able to report food items consumed during school recess meals using MEDAL, albeit with limitations on the degree of accuracy.     

Energy‐dense fast food products cost less: an observational study of the energy density and energy cost of Australian fast foods

Objective: To examine the association between energy cost and energy density of fast food products. Methods: Twenty Sydney outlets of the five largest fast food chains were surveyed four times. Price and kilojoule data were collected for all limited‐time‐only menu items (n=54) and a sample of standard items (n=67). Energy cost ($/kilojoule) and energy density (kilojoules/gram) of menu items were calculated. Results: There was a significant inverse relationship between menu item energy density and energy cost (p<0.001). Salads had the highest energy cost, while value items, meals that included a dessert and family meals had the lowest. Conclusions: Fast food chains could provide a wider range of affordable, lower‐energy foods, use proportional pricing of larger serve sizes, or change defaults in meals to healthier options. More research is required to determine the most effective strategy to reduce the negative impact of fast food on the population's diet. Implications: Current pricing in the fast food environment may encourage unhealthier purchases.     

Development of a Digital Photographic Food Atlas as a Portion Size Estimation Aid in Japan

This study aimed to develop a digital photographic food atlas as a portion size estimation aid. Commonly consumed foods were identified from the 5512-day weighed dietary records of 644 Japanese adults. Portion sizes were determined based on the market research and distribution of food consumption in the dietary records. Each food item was classified into one of two photo types: a series of photographs showing gradually increasing portion sizes or guide photographs representing a range of portion sizes and food varieties in one photograph. Photographs of the food were taken at an angle of 42°, along with appropriate reference objects such as chopsticks. In total, 209 food and dish items were included in the food atlas. Series of photographs were taken for 105 items that are not usually served in predetermined amounts (e.g., rice and pasta), whereas guide photographs were taken for 104 items usually served in predetermined amounts (e.g., bananas and cookies). Moreover, photographs were taken for 12 kinds of household measurement items, such as cups and glasses. The food atlas could be a valuable tool for estimating the portion size in dietary surveys. Evaluating the validity of this food atlas for portion size estimation is warranted.     

Accuracy of food photographs for quantifying food servings in a lunch meal setting among Danish children and adults

Background

Visual aids, such as food photographs, are widely used in estimating food quantities in dietary surveys. The present study aimed to assess how accurately Danish adults and children can estimate food portion sizes using 37 series of photographs illustrating four to six different portion sizes under real‐life conditions; determine whether adults were more accurate than children; and estimate the error caused by using portion size photographs to estimate weights of foods consumed in macronutrient calculation.

Methods

Six hundred and twenty‐two adults and 109 children were recruited in three workplace canteens and in two schools, respectively, to estimate their lunchtime portions based on photographs. Participants were instructed to keep the foods separated on their plate when taking lunch. Participants thereafter estimated their own portions by looking at the relevant series of photographs. The actual food portions were then weighed.

Results

The proportion of correct estimations was 42% overall (range 19–77%). The mean difference (%) between estimated and actual weight was 17% (range 1–111%). Small portion size photographs were more often used correctly compared to larger portion photographs. Children had as many correct estimations as adults, although they overestimated portions more. Participants using fractions of (or more than) one photograph to estimate the portion of a food had significantly larger errors. When calculating the macronutrient content of a weekly menu using the estimated portion sizes, protein had the largest error (29%).

Conclusions

When used in a real‐life situation, the portion size photographs validated in the present study showed a certain inaccuracy compared to the actual weights.     

Accuracy and Reliability of Direct Observations of Home-Packed Lunches in Elementary Schools by Trained Nutrition Students

Increased attention has been directed toward the school food environment because children consume important contributions toward their daily food intake while at school. In Canada, most elementary school students bring a lunch to school and there are minimal data on the composition and consumption of these lunches. Dietary assessment of home-packed lunches is challenging compared with assessment of standardized school meals due to greater diversity of items, nonstandard portions, and opaque containers. We assessed accuracy and reliability of a food observation method whereby upper-year nutrition students (n=15) were trained to assess packed lunch contents and intake in elementary schools. Accuracy and reliability was assessed during 2010-2011 in three observational phases: sample lunches, volunteer-consumed lunches, and elementary school students' lunches (n=32). Observers accurately identified 96% and 95% of items in the sample and volunteer lunches, respectively. Similarly, they accurately reported portion sizes for 86% and 94% of the items in the sample and volunteer lunches, thus showing improvements in successive phases. Interobserver reliability for amount consumed, by portion size and macronutrient content, ranged from 0.79 to 0.88 in the volunteer-consumed lunches and 0.78 to 0.86 in the students' lunches, with a majority ≥0.80. It is noteworthy that the analyses for the amount consumed were conducted as absolute amounts with no allowances for discrepancies, which differs from other interobserver reliability assessments where as much as 25% discrepancy is considered agreement. Observers with prior nutrition knowledge assessed packed lunch contents and intake accurately and reliably by direct observation in an elementary school setting.     

Position paper on the need for portion‐size education and a standardised unit of measurement

Large portion sizes contribute to weight gain in western societies. Portion‐size interventions, aids and education can be effective in helping prevent weight gain, but consumers are unsure what appropriate portions are and express confusion about existing guidelines. A lack of clarity about suggested serving size recommendations is a major barrier to food portion‐size control. Therefore, standardised measurement units and unambiguous terminologies are required. This position paper summarises the evidence regarding the impact and importance of portion‐size education and estimation, and outlines strategies for improving consumer understanding and application of this through the development of an international food measurement system and a range of appropriate portion control tools. In this position paper, the authors call for the standardisation of food volume measurement terminologies, units, implementation recommendations, as well as consumer education. The target audience for this paper includes nutrition and behavioural researchers, policy makers, and stakeholders who potentially influence and implement changes in national food measurement systems, which in turn impact on consumer choice.     

Serving larger portions of fruits and vegetables together at dinner promotes intake of both foods among young children

Serving larger portions of energy-dense foods has been shown to promote children's energy intake at meals. Whether larger portions increase children's intake of both fruits and vegetables (F&V) is less clear. A 2×2 within-subjects design systematically varied portion sizes of fruit (75 vs 150 g) and vegetable (75 vs 150 g) side dishes served at dinner. Children's F&V liking was measured using a validated tasting method. Thirty children aged 4 to 6 years were tested in a laboratory setting at 5:00 pm on weekdays from November 2008 through March 2009. Mixed linear models were used to determine effects of fruit portion size, vegetable portion size, and their interaction on food and energy intakes. Data are presented as model-based means±standard error unless otherwise indicated. When portions were doubled, children increased their vegetable intake by 37% (12±4 g; P<0.01) and their fruit intake by 70% (41±6 g; P<0.01). Vegetable portion size effects were not influenced by offering more fruit and vice versa. Portion size effects were limited to children who liked that particular food. Total meal energy intake did not vary by portion size condition. These results indicate that serving larger F&V portions at meals can be used to promote young children's intake of both foods without influencing total meal energy intake. Effects were not seen in children who disliked F&V, suggesting a need to combine increased F&V portions with strategies to increase their acceptance.     

Estimation of food portion size using photographs: validity, strengths, weaknesses and recommendations

Photographs are valuable aids in the estimation of food portion sizes and are easy to use in dietary surveys. As with other methods, employing photographs to estimate portion sizes consumed produces errors due to the method itself and errors from other sources such as poor recall of amounts actually eaten. This study was aimed at the first type of error and investigated errors due to the visual perception of food portions from food photographs in the absence of recall biases. Two hundred and seventy women were presented with various amounts of foods and asked to indicate the portion sizes using appropriate sets of photographs. The photographs showed three portion sizes (small, medium, large) for each of 45 foods commonly found in the French diet. The portions of real food estimated by subjects were prepared to the same weights as the portions photographed. Estimates of portion sizes were compared to the weighed amounts. They were found to be accurate within 25% in most cases. Except for three foods, errors on estimates were seen for one or more portions per food. Two patterns of errors were identified. For 22 foods, the small portion sizes were overestimated and the large portion sizes underestimated, but no error occurred with the medium portion. For 20 other foods, the three portion sizes were either all underestimated or all overestimated. The first pattern of error may be due to a general tendency to avoid extreme response categories, while the second pattern of error may be related to biased visual perception. In general, there was no obvious way to link the patterns of errors with the type or physical appearance of the foods. In conclusion, the photograph method is recommended for the assessment of portion sizes, provided that great care is taken to suggest the volume of the food portions in the photographs and in selecting a range of portions which encompasses the range of amounts of food actually consumed in the diet.     

The availability and accessibility of nutrition information in fast food outlets in five states post‐menu labelling legislation in New South Wales

Objectives: 1) Explore the availability and accessibility of fast food energy and nutrient information post‐NSW menu labelling legislation in states with and without menu labelling legislation. 2) Determine whether availability and accessibility differed compared with pre‐menu labelling legislation in NSW. Methods: We visited 210 outlets of the five largest fast food chains in five Australian states to observe the availability and accessibility of energy and nutrient information. Results were compared with 197 outlets surveyed pre‐menu labelling. Results: Most outlets (95%) provided energy values, half provided nutrient values and 3% provided information for all menu items. The total amount of information available increased post‐NSW menu labelling implementation (473 versus 178 pre‐implementation, p<0.001); however, fewer outlets provided nutrient values (26% versus 97% pre‐implementation, p<0.001). Conclusions: Fast food chains surveyed had voluntarily introduced menu labelling nationally. However, more nutrient information was available in‐store in 2010, showing that fast food chains are able to provide comprehensive nutrition information, yet they have stopped doing so. Implications: Menu labelling legislation should compel fast food chains to provide accessible nutrition information including nutrient values in addition to energy for all menu items in‐store. Additionally, public education campaigns are needed to ensure customers can use menu labelling.     

The pattern of food consumption related to energy intake

Food habits of 36 men were recorded by means of a 7-d weighed inventory. Those recording higher energy intakes tended to consume a greater number of portions of some food items, but portion weights were not related to the energy intake. Those with higher energy intakes consumed a greater number of large meals; the relationship between energy intake and frequency of meals depended on the definition of a meal. There was no correlation between energy intake and variety of food consumed.     

Comparison of a food frequency questionnaire with an online dietary assessment tool for assessing preschool children’s dietary intake

Background: It is important to assess the dietary habits of children as they progress from early childhood to adolescence. However, there are few validated tools available to assess the diet of this group of children. The present study aimed to investigate the relative validity of a food frequency questionnaire (FFQ) developed for use in a biennial longitudinal study. Methods: The parents of 216 Belgian–Flemish preschool children completed a FFQ (including questions on 77 food groups) and an online dietary assessment tool for three nonconsecutive days on their child’s diet. Intakes of energy, macronutrients, fibre, calcium and 20 food groups recorded by both methods were compared using Spearman’s correlations, Wilcoxon’s signed rank test and Bland and Altman analyses. Results: At the group level, good agreement was found for energy, fat and protein intake, an overestimation was found for carbohydrates (5.6%) and fibre (13.3%), and an underestimation was found for calcium (9%). For the food groups, overestimation as well as underestimation and good agreement were found, although overestimation was most common. Good agreement was found in ranking the children’s fruit (r = 0.53), beverages (r = 0.58–0.76), soup (r = 0.51), breakfast cereals (r = 0.55) and calcium (r = 0.59) intake according to both methods. Conclusion: The results obtained revealed that the FFQ was a useful alternative for estimating energy and macronutrient intake at a group level; however, when used to estimate fibre and calcium intake, respectively, over‐ and underestimation need to be considered. The short reference period (3 days) may have compromised agreement in ranking and agreement at the individual level.     

Effects of portion size and energy density on young children's intake at a meal

BACKGROUND: Large portions of energy-dense foods are one feature of obesity-promoting dietary environments. Entrée portion size has been shown to influence energy intake at meals by young children. The role of energy density (ED) in children's response to portion size, however, is unknown. OBJECTIVE: We aimed to test the effects of portion size and ED on children's food and energy intakes at a meal. DESIGN: Participants were 53 (28 girls and 25 boys; 15 Hispanic, 20 black, 16 white, 2 other race) 5- to 6-y-old children [mean (+/-SD) body mass index percentile: = 61 +/- 28]. A 2 x 2 within-subjects design was used to manipulate entrée portion size (250 compared with 500 g) and ED (1.3 compared with 1.8 kcal/g). Fixed portions of other familiar foods were provided. Weighed intake, food preference, and weight and height data were obtained. RESULTS: Effects of portion size (P<0.0001) and ED (P<0.0001) on entrée energy intake were independent but additive. Energy intake from other foods at the meal did not vary across conditions. Compared with the reference portion size and ED condition, children consumed 76% more energy from the entrée and 34% more energy at the meal when served the larger, more energy-dense entrée. Effects did not vary by sex, age, entrée preference, or body mass index z score. CONCLUSIONS: These findings provide new evidence that portion size and ED act additively to promote energy intake at meals among preschool-aged children.     

Food photographs in nutritional surveillance: errors in portion size estimation using drawings of bread and photographs of margarine and beverages consumption

Food photographs are widely used as instruments to estimate portion sizes of consumed foods. Several food atlases are available, all developed to be used in a specific context and for a given study population. Frequently, food photographs are adopted for use in other studies with a different context or another study population. In the present study, errors in portion size estimation of bread, margarine on bread and beverages by two-dimensional models used in the context of a Belgian food consumption survey are investigated. A sample of 111 men and women (age 45-65 years) were invited for breakfast; two test groups were created. One group was asked to estimate portion sizes of consumed foods using photographs 1-2?d after consumption, and a second group was asked the same after 4?d. Also, real-time assessment of portion sizes using photographs was performed. At the group level, large overestimation of margarine, acceptable underestimation of bread and only small estimation errors for beverages were found. Women tended to have smaller estimation errors for bread and margarine compared with men, while the opposite was found for beverages. Surprisingly, no major difference in estimation error was found after 4?d compared with 1-2?d. Individual estimation errors were large for all foods. The results from the present study suggest that the use of food photographs for portion size estimation of bread and beverages is acceptable for use in nutrition surveys. For photographs of margarine on bread, further validation using smaller amounts corresponding to actual consumption is recommended.     

Validation of a food quantification picture book and portion sizes estimation applying perception and memory methods

We tested the applicability of EPIC-SOFT food picture series used in the context of a Hungarian food consumption survey gathering data for exposure assessment, and investigated errors in food portion estimation resulted from the visual perception and conceptualisation-memory. Sixty-two participants in three age groups (10 to <74?years) were presented with three different portion sizes of five foods. The results were considered acceptable if the relative difference between average estimated and actual weight obtained through the perception method was ≤25%, and the relative standard deviation of the individual weight estimates was <30% after compensating the effect of potential outliers with winsorisation. Picture series for all five food items were rated acceptable. Small portion sizes were tended to be overestimated, large ones were tended to be underestimated. Portions of boiled potato and creamed spinach were all over- and underestimated, respectively. Recalling the portion sizes resulted in overestimation with larger differences (up to 60.7%).     

Meals, snacks and food choices in Brazilian shift workers with high energy expenditure

Objective To describe the food intake of garbage collectors, who works in three shifts, in terms of meal and snack frequency, content, time distribution and the contribution of various popular foods to the total diet. Methods Sixty‐six Brazilian garbage collectors, who work in morning, afternoon, and night shift, participated in the present study. The quantitative methods used were a combination of one 24‐h recall and two 24‐h records during three nonconsecutive work days. The qualitative method used was the food‐based classification of eating episodes model modified in order to define meals or snacks in three categories of events: meals with three food groups of high nutrient density (three HND meals), meals with two food groups of high nutrient density (two HND meals) and snacks, composed of only one food category of high nutrient density. Results The total number of eating events per day was significantly higher for night shift workers. Over 24‐h, ‘two HND meals’ were the most common events and contributed the most energy, in all three shifts. Night shift workers ate more at dawn and less in the morning than other shifts. In all three shifts, meat was the most important food contributing to energy intake. Conclusion Different work schedules did not affect the relative frequency of meal types and snacks or their contribution to daily energy intake, but affected the daily distribution of eating events, with a redistribution of intake from day to night in night shift workers.     

Dimensions of Sandawe diet

Rural African children consuming plant‐based diets low in animal products are at risk for sub‐optimal zinc nutriture. Consequently, we investigated indigenous dietary strategies for inproving the zinc nutriture of rural southern Malawian and Ghanaian children.

Seasonal dietary intakes, and the portion sizes of foods consumed by 4–6 year old Malawian and Ghanaian girls (n = 112) were determined from 3‐day weighed food records. The optimal combination of food items for enhancing zinc bioavailability was determined by comparing the zinc content, and the phytate‐to‐zinc molar ratio (PZ) of isocaloric meals and snacks consumed by these girls. The energy content and portion sizes of the recommended meals and snacks were based on actual average intakes.

Results showed that in Malawi the amount of available zinc could be enhanced by using refined corn flour nsima or a non‐traditional fermented corn dough nsima with relishes prepared from small fish, and snacks with moderate to low PZ. In Ghana, fermented corn dough banku, or cocoyam, for root‐based meals, together with a soup/stew of small fish, and zinc‐dense snacks were recommended.     

The portion size effect and overconsumption – towards downsizing solutions for children and adolescents – An update

The portion size effect (PSE), where more is eaten when large amounts are offered, is robust, reliable and enduring. Although it is not known what drives the PSE, amount served may act as a guide to how much should be eaten. Over time, consumers become accustomed to particular amounts of food as the ‘social norm’ and so large portion sizes are treated as typical. For children and adolescents who are forming eating habits, long‐term exposure to large portion sizes of snacks and meal items may encourage overconsumption. Therefore, offering smaller portions to suit the age and stage of children and young people should offer a potential solution to the PSE. We have developed a series of downsizing strategies to test the effect of providing smaller portions of snacks and meal items in pre‐school children, adolescents and families. One potential consequence of downsizing is that compensation may occur, in which smaller portion sizes drive intake of other foods. Therefore, in examining downsizing strategies, measures of compensation elsewhere in the meal or across the overall diet are important. Our studies indicate that it is both feasible and desirable to offer ‘me‐sized’, smaller portions for children to facilitate portion control as food preferences and eating habits are developed. However, strategies for young adults and adolescents are more challenging and require further investigation.