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PubMed1997

Within- and between-person variations in portion sizes of foods consumed by the Japanese population.

There has been considerable controversy about the utility of asking separate questions on portion sizes in addition to items on consumption frequencies in food frequency questionnaires. One argument against this type of inquiry is that, for most foods, within-person variation of portion size is greater than between-person variation, making it difficult to characterize "usual" or long-term average serving sizes. The authors studied the relative effects of within- and between-person variances in portion sizes of 69 food items using three-day food record data collected from 335 Japanese men and women. Total variance in the portion size for each food was partitioned into within- and between-person components by analysis of variance. Although the ratios of within- to between-person variances in log(e)-transformed portion sizes were > 1.0 for the majority of foods (50 of 69 items, median = 1.7), they were smaller than or close to unity for subgroups of foods that were the major sources of nutrient variables of relevance to diet-cancer associations, such as total energy (rice, calcium (milk), sodium (pickled vegetables), and alcohol (beer, shochu, whiskey). These results indicate that the relative contributions of within- and between-person variations in portion size may vary among foods, and therefore investigators should consider the balance between the advantages and disadvantages of obtaining portion size data separately from intake frequencies when designing food frequency questionnaires.

Adult↗
PubMed2005

An experimental evaluation of a group- versus computer-based intervention to improve food portion size estimation skills.

The ability to accurately estimate and measure food portion sizes is important for preventing and treating obesity. This study describes the development, implementation and evaluation of a group- versus computer-based intervention to improve food portion estimation abilities using real food and food models. A convenience sample of 76 women was randomly assigned to one of three conditions: computer training, group training or a waitlist control condition. Assessments at baseline and 2 weeks post-intervention included portion size testing using real foods and food models, self-efficacy for judging portion sizes and using measuring utensils, and knowledge of portion information. At baseline, greater estimation errors were observed for amorphous foods. No group by time interaction was observed on estimation of real foods; however, both the computer and group training resulted in significant improvements in estimating the size of food models, greater self-efficacy for judging portion sizes and more accurate knowledge of portion information compared with the control condition. Process measures indicated that the group training was deemed more helpful and more personally relevant to the participants.

Adult↗
PubMed2006

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

BACKGROUND: 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. OBJECTIVES: 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. DESIGN: 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. SUBJECTS: One hundred and thirty-five adults aged 18 to 90 years and 210 children aged 4 to 11 years. RESULTS: 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%. CONCLUSIONS: 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.

Adolescent↗
PubMed1988

Variability in portion sizes of commonly consumed foods among a population of women in the United States.

The use of food frequency questionnaires for measuring dietary intake has become widespread in epidemiologic studies. It has been suggested that inquiring about a person's usual serving size of each food, in addition to the frequency of consumption, will improve the accuracy of this method. This approach implies that individuals characteristically eat a specific amount of any particular food, and that this amount can be reported with reasonable accuracy. To investigate the variability of portion sizes, the authors analyzed data for 68 commonly consumed foods, based on four one-week weighed diet histories recorded by 194 Boston-area women aged 34-59 years during 1980 and 1981. For each food, total population variance in portion size was partitioned into within-person (intraindividual) and between-person (interindividual) components. For all but seven food items (yogurt, liver, mixed vegetables, watermelon, pancakes/waffles, cold cereal, and cooked cereal) the within-person variance in portion size exceeded the between-person variance. The mean of the within-person to between-person variance ratios, after exclusion of two outlying foods, was 3.4 for untransformed portion sizes, and 3.2 after portion sizes were loge-transformed. Foods with a high within-person variance also tended to have a high between-person variance. The dominance of within-person variance in portion sizes suggests that the concept of usual portion size is complex, and that subjects may experience substantial difficulty in specifying their "usual" portion size. The smaller contribution of between-person variance to the total variance in portion size suggests that specification of a standard portion size by the investigator may not introduce a large error in the estimation of food and nutrient intake.

Adult↗
PubMed2003

Portion size adds limited information on variance in food intake of participants in the EPIC-Potsdam study.

Food-frequency questionnaire (FFQ) data should reflect interindividual variation and therefore measure variance in intake among populations. We conducted this analysis to evaluate the relevance of separate portion size questions to the interindividual variation in food intake. The contribution of portion size questions to the variance in food intake was quantified and compared with the variance when group-specific portion sizes would be assigned, using 26,764 FFQ of the European Investigation into Cancer and Nutrition (EPIC)-Potsdam Study. Groups were defined according to gender, age (<50 y, >/=50 y) or body mass index (BMI) (<26 kg/m(2), >/=26 kg/m(2)). The FFQ inquired about both consumption frequency and portion size. Linear regression models for each food item were fit with intake (g/d) as dependent variables and frequency of intake as independent variables. The mean coefficient of determination (R(2)) for the different food items explained by frequency only was 84.0% (71.2-95.7%). The R(2) for gender-, age- and BMI-specific frequencies of intake did not markedly alter the overall results. We conclude that the omission of individual portion size information would probably result in a notable reduction of interindividual variance. However, to reduce the respondents' burden and to increase data completeness in self-administration in large epidemiologic studies, the assignment of a constant portion size seems to be adequate. The variance was not increased markedly when constant gender-, age- and BMI-specific portion sizes were applied, thus supporting the assignment of an overall portion size.

Age Distribution↗
PubMed2005

The influence of food portion size and energy density on energy intake: implications for weight management.

The increase in the prevalence of obesity has coincided with an increase in portion sizes of foods both inside and outside the home, suggesting that larger portions may play a role in the obesity epidemic. Although it will be difficult to establish a causal relationship between increasing portion size and obesity, data indicate that portion size does influence energy intake. Several well-controlled, laboratory-based studies have shown that providing older children and adults with larger food portions can lead to significant increases in energy intake. This effect has been demonstrated for snacks and a variety of single meals and shown to persist over a 2-d period. Despite increases in intake, individuals presented with large portions generally do not report or respond to increased levels of fullness, suggesting that hunger and satiety signals are ignored or overridden. One strategy to address the effect of portion size is decreasing the energy density (kilojoules per gram; kilocalories per gram) of foods. Several studies have demonstrated that eating low-energy-dense foods (such as fruits, vegetables, and soups) maintains satiety while reducing energy intake. In a clinical trial, advising individuals to eat portions of low-energy-dense foods was a more successful weight loss strategy than fat reduction coupled with restriction of portion sizes. Eating satisfying portions of low-energy-dense foods can help to enhance satiety and control hunger while restricting energy intake for weight management.

Adolescent↗
PubMed1992

Influence of individually estimated portion size data on the validity of a semiquantitative food frequency questionnaire.

Using data from a Danish dietary validity study, we evaluated the influence of including individually estimated portion size data on the validity of a semiquantitative food frequency questionnaire. A total of 144 subjects, aged 40-64 years were included. Correlation coefficients and classification of subjects into quintiles according to their intake of foods and nutrients were used to compare questionnaire data, with and without individually estimated portion size data, with data obtained by 2 x 7 days weighed diet records. For men, the mean correlation coefficient for food group comparisons was 0.47 when information about individually estimated portion sizes for food items that do not come in natural units was included in the analysis. Using a common average portion size reduced the mean correlation coefficient to 0.45. For women, similar changes were observed (0.36 to 0.35). For nutrients the mean values for the comparison changed from 0.51 to 0.49 and from 0.39 to 0.40 for men and women, respectively. For both men and women the classification into quintiles according to their intake of foods and nutrients showed only minor differences. We conclude that little extra information was gained by including individual portion size information for food items that do not come in natural units. This may reflect that portion sizes are of minor importance compared with frequencies or that the relevant individual portion sizes were not estimated correctly.

Adult↗
PubMed2005

An evaluation of a colour food photography atlas as a tool for quantifying food portion size in epidemiological dietary surveys.

OBJECTIVE: To test the validity of a colour food photography atlas for quantifying portion size eaten compared with weighed foods. DESIGN: The colour food photography atlas was prepared by cooking, weighing and taking digital photographs of three portion sizes of 434 foods and beverages typical of the Italian diet. SUBJECTS AND INTERVENTIONS: In all, 448 male and female volunteers aged 6-60 y from a wide variety of social backgrounds completed 9075 assessments of food portions eaten at lunch and dinner in relation to a set of colour food photographs during 8 weeks of investigation. The amounts of foods eaten by individuals in five different cafeterias in Pavia, Northern Italy, were weighed by trained investigators at the time of serving and, within 5-10 min of the end of the meal, each subject was asked to quantify all foods consumed with reference to one of the three food photographs or in terms of virtual portions among those shown in the photographs. RESULTS: Multiple regression analysis shows that weights of portion sizes chosen from the set of photographs are significantly associated (P<0.05) to weights of eaten portions (beta=0.81; R(2)=0.70) and are independent of age, gender and BMI. The differences between mean weights of the portions chosen by individuals from photographs and mean weights of eaten foods are significant for all food categories (P<0.05), except for bread. However, because of the very large number of observations, the mean differences are very small (range: from +23.2 g (+11.2%) for first courses to -1.3 g (-2.7%) for bread). Bland-Altman plots show that first courses limits of agreement are wide because the dispersion is increasing while weights are rising. CONCLUSIONS: The use of a series of three photographs and virtual portion sizes being associated with relatively small errors, our findings support the validity of using this colour food photography atlas as a tool for quantifying food portion size in epidemiological dietary surveys on different age groups of Italian subjects.

Adolescent↗
PubMed2000

Cognitive strategies for reporting portion sizes using dietary recall procedures.

OBJECTIVES: To examine recall strategies used by interview respondents when making judgments about portion size and to better understand how respondents use various portion-size aids. DESIGN: Study participants were separated into groups, each using a different set of portion-size estimation aids: (a) 2-dimensional paper aids presented in stacks, (b) 2-dimensional aids, cut out and presented on rings, (c) household-type aids, and (d) a combination of 2- and 3-dimensional aids, many of which are used in national government surveys. Respondents gave a "quick list" of foods consumed the previous day and practiced cognitive thinking skills. Then the interviewer selected at least 2 solid, 2 liquid, and 2 amorphous foods for probing. Respondents were asked to think aloud as they reported how much they ate of each food. Types and frequencies of cognitive strategies used for portion-size estimation were determined. SUBJECTS: Interviews of 1 to 1 1/2 hours were conducted with 76 adults aged 18 to 65 years. Participants were recruited to obtain a mix of races, ages, educational levels, and genders. RESULTS: The most frequently used strategy was visualization and comparison to aids. Others strategies were known amounts, estimations based on known amounts, visualization of volume or a container, and actions such as pouring or moving hands to the mouth. Respondents preferred aids that were similar in size and shape to actual portions consumed for liquid or amorphous food and preferred the ruler for solid foods. APPLICATIONS: To obtain the best data from dietary recalls, expect answers that are possible for respondents to give, supply respondents with aids that help them recall amounts consumed, and guide respondents to appropriate aids that help them formulate focused responses.

Adolescent↗
PubMed2006

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.

Adolescent↗
PubMed2004

Swallowing thresholds of mandibular implant-retained overdentures with variable portion sizes.

We analysed the effect of three portion sizes Optocal Plus (small, medium and large) on swallowing thresholds in subjects with either conventional complete dentures or mandibular implant-retained overdentures (transmandibular and permucosal cylindric implants). Tests were carried out in 52 women and 15 men (mean age 59 years) 4 years after treatment in a randomised controlled clinical trial. The results indicated that the degree of mucosal support for the mandibular denture did not affect the number of chewing strokes, time till swallowing or swallowed particle size. Only the chewing rate differed: subjects wearing mandibular implant-retained overdentures chewed the food at a higher rate than complete-denture wearers. With larger portion sizes, subjects needed significantly more chewing strokes and time until swallowing and they would have swallowed larger particles. Men chewed their food more efficiently than women, as they used the same number of chewing strokes and time, but achieved a greater particle size reduction at the swallowing moment.

Adult↗
PubMed1992

Validation of a method for the estimation of food portion size.

In the context of the planning phase of a large cohort study on dietary habits and cancer, we have developed a food frequency questionnaire on usual food intake, which includes a set of pictures to estimate the portion size of 23 different dishes. The validity of the estimation of portion size of recently consumed foods has been questioned by other researchers. To validate the use of pictures, we organized a field trial with 103 volunteers. They were invited to a dinner where standard Italian dishes were offered (total 17 foods); all of the portions they chose were recorded and weighed. The following day, we interviewed the volunteers on what they consumed during the dinner, and we compared the weight of the food actually eaten with the weight of the food represented in the pictures. The volunteers overestimated the portion size by more than 20% for six foods and underestimated the portion size by more than 20% for four foods. In addition, we found a tendency toward overestimation of portion size by those who ate smaller portions and underestimation, by those who ate larger portions ("flat slope syndrome").

Adult↗
PubMed2004

The effect of a dietary preload on estimation of usual food portion size by photograph in female volunteers.

BACKGROUND: The aim of this study was to investigate whether a subject's level of satiety influences perception of their usual portion size. METHODS: A total of 62 school children were recruited for the pilot study. Half of the group assessed food photographs for their usual portion size before lunch, and half after lunch. For the main study, 55 female students were recruited to test within-subject variation in perception of usual portion size before and after consuming a preload. RESULTS: Significant differences in perception of portion size were found for four of the six foods used. CONCLUSION: Some subjects' perception of their usual portion size was influenced by their level of satiety. Further study is needed to investigate this using a wider variety of food photographs and an alternative preload.

Adult↗
PubMed2004

Increased portion size leads to increased energy intake in a restaurant meal.

OBJECTIVE: Eating frequently in restaurants is one of the behaviors associated with obesity. This study examined whether increasing the portion size of an entrée affected energy intake at a restaurant meal. RESEARCH METHODS AND PROCEDURES: In a cafeteria-style restaurant on different days, the size of a pasta entrée was varied from a standard portion (248 g) to a large portion (377 g). The entrée price was not changed. Intake of the entrée was determined by covertly weighing each dish before and after the meal; intake of all other foods was determined by estimating the percent consumed. The 180 adult customers who purchased the entrée also completed a survey in which they rated characteristics of the meal, including the appropriateness of the entrée portion size and the amount that they ate compared with their usual meal. RESULTS: Portion size had a significant effect on intake of the entrée (p < 0.0001). Compared with customers who purchased the standard portion, those who purchased the larger portion increased their energy intake of the entrée by 43% (719 kJ; 172 kcal) and of the entire meal by 25% (664 kJ; 159 kcal). There was no difference between the two groups of customers in ratings of the appropriateness of the portion size or of the amount that was eaten in relation to their usual meal. DISCUSSION: In a restaurant setting, increasing the size of an entrée results in increased energy intake. These results support the suggestion that large restaurant portions may be contributing to the obesity epidemic.

Adolescent↗
PubMed2004

Influence of individually estimated portion size on the assessment of nutritional risk in colorectal cancer in Portugal.

We evaluated the influence of individually estimated portion sizes on the estimate of nutrient related risk of colorectal cancer, using data from a Portuguese hospital based case-control study on diet and colorectal cancer. A total of 100 patients with colorectal adenocarcinoma (aged 15-92 years) and 211 controls (aged 36-89 years) were included. Two data sets were created for nutrient analysis, the first one allowed estimates of food intake using data on portion size as collected with visual aids during the interview. The second estimate substituted respondents' estimate with a standard portion size, as used in the semi-quantitative (SQ) food frequency approach. The two analytic approaches yielded similar energy and nutrient intakes in cases and controls. The percent range of concordance is acceptable, in the same quartile varying from 44 to 82% (mean: 56%) and very good in the same or adjacent (+/-1) quartile (mean: 91%, range: 85-97%). The two estimates lead to a similar pattern of multivariate odd's ratio, however the SQ estimates resulted in more significant findings. We conclude that little extra information is gained by including individual portion size information when assessing diet-related risk of colorectal cancer.

Adenocarcinoma↗
PubMed1988

Estimation of food portion sizes: effectiveness of training.

This study compared the effectiveness of two types of training on the ability to estimate food portion sizes. Training consisted of a 10-minute group session in which subjects practiced measuring various solid and liquid foods with household measures. A second group of subjects viewed food models of solids and liquids. Immediately following training, subjects individually quantified portion sizes of foods displayed as a breakfast, lunch, and dinner. A third group, whose members received no training, also estimated the same food portion sizes. Results indicated no statistically significant difference (p greater than .05) between the two types of training using both parametric and non-parametric tests. When the trained groups were combined and compared with the untrained group, MANOVA analysis indicated training made a significant difference (p less than .05) in improving estimation for some food items. A Kolmogorov-Smirnov test also supported the hypothesis that training improved estimation for some, but not all, food items. Although a significant difference was not found for all food items, the data lend some support to the practice of using food models or household measures to enhance the ability to estimate food portion sizes more accurately, even when training is undertaken in short group sessions.

Dietetics↗
PubMed2006

Larger portion sizes lead to a sustained increase in energy intake over 2 days.

OBJECTIVE: We tested the effect on energy intake of increasing the portion size of all foods and beverages served over 2 consecutive days. DESIGN: The study used a randomized crossover design. SUBJECTS/SETTING: Subjects were 32 adults from a university community. INTERVENTION: For 2 consecutive days in each of 3 weeks, subjects ate their main meals in a controlled setting and were given snacks for consumption between meals. We used the same two daily menus each week, but varied the portion sizes of all foods and beverages served in a given week (either 100%, 150%, or 200% of baseline amounts). MAIN OUTCOME MEASURES: Energy intake and ratings of hunger and satiety were measured. STATISTICAL ANALYSES PERFORMED: A linear mixed model with repeated measures was used. RESULTS: There was a significant effect of portion size on energy intake in both men and women (P<0.0001). Increasing portions by 50% increased daily energy intake by 16% (women: 335 kcal/day; men: 504 kcal/day), and increasing portions by 100% increased intake by 26% (women: 530 kcal/day; men: 812 kcal/day). Energy intake did not differ between the 2 days of each week. Daily ratings of fullness were lowest in the 100% portion condition (P=0.0004), but did not differ significantly in the 150% and 200% conditions. CONCLUSIONS: Increasing the portion size of all foods resulted in a significant increase in energy intake that was sustained over 2 days. These data support suggestions that large portions are associated with excess energy intake that could contribute to increased body weight.

Adult↗
PubMedDate not supplied

[New techniques in nutritional surveys and food educational programs: volumetric dietetics for portion size assessment].

Data in literature show that body weight in adults and children seems to be related to portion sizes more than to food choices and people are more reluctant to give up favourite foods than to reduce portions. So several scientific societies in USA have recently emphastzied the need to select appropriate portion sizes. At the same time, studies on cognitive strategies show that the best method to help people to remember how much they eat is visualisation/comparison to tridimensional visual aids. So a new technique for evaluating portion sizes, based on comparison of portions to volume of usual objects (baseball, dice, deck of cards) appeared in the last years, in nutritional surveys and food educational projects. Our team, since 1990, appointed a volumetric assessment based on comparison of foods to the fist, palm, fingers of the examined subject; this system has been experienced with success for a long time both in individual dietetics and in food educational projects or surveys. Since the interest for this new technique is rising, the aim of this review is to introduce the method and to delineate the applications in nutritional surveys or educational projects in national and international literature. This method, simple practical and intelligible, seems to be addressed to a wide development in the future.

Diet↗