The international food unit: a new measurement aid that can improve portion size estimation

Training flexible spatial-cognitive estimation strategies using augmented reality

We investigated the potential for augmented reality (AR) as a training aid for spatial estimation skills. Though there are many tools to support spatial judgments, from measuring cups to rulers, not much is known about training spatial skills for retention and transfer. Display of AR was manipulated to train the spatial skill of portion estimation. In Experiment 1, an AR-aided strategy of creating smaller portions out of a larger example amount was compared to a no-AR control condition. This manipulation was based on previous non-AR experiments where amorphous foods were better estimated when divided into smaller portions. There was a significant benefit of estimating using a solid AR shape. In Experiment 2, cognitive anchoring was manipulated. Using meaningful AR anchors resulted in the best performance and most learning. We conclude that spatial estimation skills can be combined with mental strategies and trained via AR.

Estimation of Plate and Bowl Dimensions for Food Portion Size Assessment in a Wearable Sensor System

Automatic food portion size estimation (FPSE) with minimal user burden is a challenging task. Most of the existing FPSE methods use fiducial markers and/or virtual models as dimensional references. An alternative approach is to estimate the dimensions of the eating containers prior to estimating the portion size. In this article, we propose a wearable sensor system (the automatic ingestion monitor integrated with a ranging sensor) and a related method for the estimation of dimensions of plates and bowls. The contributions of this study are: 1) the model eliminates the need for fiducial markers; 2) the camera system [automatic ingestion monitor version 2 (AIM-2)] is not restricted in terms of positioning relative to the food item; 3) our model accounts for radial lens distortion caused due to lens aberrations; 4) a ranging sensor directly gives the distance between the sensor and the eating surface; 5) the model is not restricted to circular plates; and 6) the proposed system implements a passive method that can be used for assessment of container dimensions with minimum user interaction. The error rates (mean ± std. dev) for dimension estimation were 2.01% ± 4.10% for plate widths/diameters, 2.75% ± 38.11% for bowl heights, and 4.58% ± 6.78% for bowl diameters.

Evaluating an integrated nutrition and mathematics curriculum: primary school teachers' and students' experiences

OBJECTIVE

To present the process evaluation of a curricular Cross-curricular Unit on Portion Size (CUPS) program that integrates nutrition and mathematics, describing teacher and student perspectives on the intervention.

DESIGN

Semi-structured interviews and focus groups were conducted following the implementation of the CUPS program during a pilot randomised controlled trial designed to evaluate efficacy for improved portion size estimation. Lessons involved experiential learning using food models and mathematics cubes and focussed on portion size, food groups, volume and capacity. Data were collected immediately post-intervention and analysed using an inductive thematic approach.

SETTING

Primary schools in Newcastle, Australia.

PARTICIPANTS

Year 3 and/or 4 teachers (n 3) and their students (n 15).

RESULTS

Teachers believed the programme supported the learning of nutrition concepts, with the majority of students enjoying the lessons, cubes and food models. Teachers indicated most students were engaged and became more aware of healthy eating and serve size recommendation. Although teachers enjoyed and valued the lessons, they suggested that the integration of volume and capacity should be further improved in order to address the time barrier for teaching nutrition.

CONCLUSION

The process evaluation reports on challenges and successes of implementing an integrative nutrition programme. This teaching approach could be useful and successful when aligned with teacher' and student' needs. Based on participant feedback, lessons could be refined to enhance integration of mathematics content and to support student learning.

A Novel Approach to Dining Bowl Reconstruction for Image-Based Food Volume Estimation

Knowing the amounts of energy and nutrients in an individual's diet is important for maintaining health and preventing chronic diseases. As electronic and AI technologies advance rapidly, dietary assessment can now be performed using food images obtained from a smartphone or a wearable device. One of the challenges in this approach is to computationally measure the volume of food in a bowl from an image. This problem has not been studied systematically despite the bowl being the most utilized food container in many parts of the world, especially in Asia and Africa. In this paper, we present a new method to measure the size and shape of a bowl by adhering a paper ruler centrally across the bottom and sides of the bowl and then taking an image. When observed from the image, the distortions in the width of the paper ruler and the spacings between ruler markers completely encode the size and shape of the bowl. A computational algorithm is developed to reconstruct the three-dimensional bowl interior using the observed distortions. Our experiments using nine bowls, colored liquids, and amorphous foods demonstrate high accuracy of our method for food volume estimation involving round bowls as containers. A total of 228 images of amorphous foods were also used in a comparative experiment between our algorithm and an independent human estimator. The results showed that our algorithm overperformed the human estimator who utilized different types of reference information and two estimation methods, including direct volume estimation and indirect estimation through the fullness of the bowl.

Effect of Water Hardness on Catechin and Caffeine Content in Green Tea Infusions

The health benefits of green tea are associated with its high catechin content. In scientific studies, green tea is often prepared with deionized water. However, casual consumers will simply use their local tap water, which differs in alkalinity and mineral content depending on the region. To assess the effect of water hardness on catechin and caffeine content, green tea infusions were prepared with synthetic freshwater in five different hardness levels, a sodium bicarbonate solution, a mineral salt solution, and deionized water. HPLC analysis was performed with a superficially porous pentafluorophenyl column. As water hardness increased, total catechin yield decreased. This was mostly due to the autoxidation of epigallocatechin (EGC) and epigallocatechin gallate (EGCG). Epicatechin (EC), epicatechin gallate (ECG), and caffeine showed greater chemical stability. Autoxidation was promoted by alkaline conditions and resulted in the browning of the green tea infusions. High levels of alkaline sodium bicarbonate found in hard water can render some tap waters unsuitable for green tea preparation.

Portion size estimation in dietary assessment: a systematic review of existing tools, their strengths and limitations

CONTEXT

Overestimation or underestimation of portion size leads to measurement error during dietary assessment.

OBJECTIVE

To identify portion size estimation elements (PSEEs) and evaluate their relative efficacy in relation to dietary assessment, and assess the quality of studies validating PSEEs.

DATA SELECTION AND EXTRACTION

Electronic databases, internet sites, and cross-references of published records were searched, generating 16 801 initial records, from which 334 records were reviewed and 542 PSEEs were identified, comprising 5% 1-dimensional tools (eg, food guides), 46% 2-dimensional tools (eg, photographic atlases), and 49% 3-dimensional tools (eg, household utensils). Out of 334 studies, 21 validated a PSEE (compared PSEE to actual food amounts) and 13 compared PSEEs with other PSEEs.

CONCLUSION

Quality assessment showed that only a few validation studies were of high quality. According to the findings of validation and comparison studies, food image-based PSEEs were more accurate than food models and household utensils. Key factors to consider when selecting a PSEE include efficiency of the PSEE and its applicability to targeted settings and populations.

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

Background

Inaccurate 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.

Methods

True 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.

Results

No 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.

Conclusions

Although 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.

Portion size and consistency as indicators of complementary food energy intake

We evaluated whether novel portion size and consistency indicators can identify children with low complementary food energy intake in southern Ethiopia. We conducted 24-h dietary recalls with caregivers of 548 children aged 6-13 months; additionally, caregivers estimated their child's usual portion size using uncooked rice and selected which of five photographs of porridges of varying consistencies most closely matched the food their child usually ate. Complementary food energy and density from the 24-h recall were used as reference values. We computed correlation coefficients and areas under receiver operating characteristic curves (AUC) and conducted sensitivity and specificity analyses to classify children with low complementary food energy intake. The median complementary food energy intakes for children 6-8, 9-11 and 12-13 months were 312, 322 and 375 kcal; median estimated portion sizes were 50, 58 and 64 ml, respectively. Estimated portion size correlated with total complementary food energy intake and with average energy and quantity consumed per feeding (r = 0.42, 0.46 and 0.45, respectively, all p < 0.001). Reported food consistency was weakly correlated with total complementary food energy intake (r = 0.18) and density (r = 0.10), and energy density of porridge only (r = 0.24, all p < 0.05). Predicted energy intake combining feeding frequency and portion size predicted inadequate energy intake better than did feeding frequency alone in infants 6-8 months [∆AUC = 0.16, 95% confidence interval (CI) 0.04, 0.28] and 9-11 months (∆AUC = 0.09, 95% CI 0.04, 0.14). Caregiver estimates of portion size can improve identification of infants with low complementary food energy intake when more robust dietary assessment is not feasible.

Integrating nutrition into the mathematics curriculum in Australian primary schools: protocol for a randomised controlled trial

Background

Nutrition education programs in schools have been effective in improving children’s knowledge and behaviours related to food and nutrition. However, teachers find it challenging to implement such programs due to overcrowded curricula. Integrating nutrition with core subjects such as mathematics could potentially address time constraints and improve the learning of both. The primary aim of this randomized controlled trial (RCT) is to evaluate the impact of a cross-curricular nutrition and mathematics program on primary school students’ portion size estimation skills. Secondary aims include impact on their nutrition knowledge, attitudes towards mathematics and evaluating the quality of the lessons.

Methods

Twelve Year 3–4 classes from Catholic schools in New South Wales, Australia will be randomised to intervention (n = 6) or control (n = 6) groups. Teachers in the intervention group will receive a professional development workshop and resources to teach 4–5 lessons on portion size and measurements across 1–4 weeks. Outcome measures include portion size estimation skills, nutrition knowledge and attitudes towards mathematics, with data collected during three school visits (pre-intervention, immediately post-intervention, 4 weeks post-intervention). Additionally, teaching quality will be assessed in both intervention and control groups and process evaluation undertaken using teacher interviews and student focus groups.

Discussion

This RCT uses an innovative approach to improve both nutrition and mathematics related learning outcomes among primary school children. It has the potential to impact teaching practices regarding integration of nutrition into curricula and enhance the implementation of nutrition education interventions.

Trial registration

Australian and New Zealand Clinical Trials Register ACTRN12619001071112 31/07/2019.

How does a simplified recipe collection procedure in dietary assessment tools affect the food group and nutrient intake distributions of the population

Technology advancements have driven the use of self-administered dietary assessment methods in large-scale dietary surveys. Interviewer-assisted methods generally have a complicated recipe recording procedure enabling the adjustment from a standard recipe. In order to decide if this functionality can be omitted for self-administered dietary assessment, this study aimed to assess the extent of standard recipe modifications in the Dutch National Food Consumption Survey and measure the impact on the food group and nutrient intake distributions of the population when the modifications were disregarded. A two-scenario simulation analysis was conducted. Firstly, the individual recipe scenario omitted the full modifications to the standard recipes made by people who knew their recipes. Secondly, the modified recipe scenario omitted the modifications made by those who partially modified the standard recipe due to their limited knowledge. The weighted percentage differences for the nutrient and food group intake distributions between the scenarios and the original data set were calculated. The highest percentage of energy consumed through mixed dishes was 10 % for females aged 19-79 years. Comparing the combined scenario and the original data set, the average of the absolute percentage difference for the population mean intakes was 1·6 % across all food groups and 0·6 % for nutrients. The soup group (-6·6 %) and DHA (-2·3 %) showed the largest percentage difference. The recipe simplification caused a slight underestimation of the consumed amount of both foods (-0·2 %) and nutrients (-0·4 %). These results are promising for developing self-administered 24-hour recalls or food diary applications without complex recipe function.

Consumer Understanding, Perception and Interpretation of Serving Size Information on Food Labels: A Scoping Review

The increase in packaged food and beverage portion sizes has been identified as a potential factor implicated in the rise of the prevalence of obesity. In this context, the objective of this systematic scoping review was to investigate how healthy adults perceive and interpret serving size information on food packages and how this influences product perception and consumption. Such knowledge is needed to improve food labelling understanding and guide consumers toward healthier portion size choices. A search of seven databases (2010 to April 2019) provided the records for title and abstract screening, with relevant articles assessed for eligibility in the full-text. Fourteen articles met the inclusion criteria, with relevant data extracted by one reviewer and checked for consistency by a second reviewer. Twelve studies were conducted in North America, where the government regulates serving size information. Several studies reported a poor understanding of serving size labelling. Indeed, consumers interpreted the labelled serving size as a recommended serving for dietary guidelines for healthy eating rather than a typical consumption unit, which is set by the manufacturer or regulated in some countries such as in the U.S. and Canada. Not all studies assessed consumption; however, larger labelled serving sizes resulted in larger self-selected portion sizes in three studies. However, another study performed on confectionary reported the opposite effect, with larger labelled serving sizes leading to reduced consumption. The limited number of included studies showed that labelled serving size affects portion size selection and consumption, and that any labelled serving size format changes may result in increased portion size selection, energy intake and thus contribute to the rise of the prevalence of overweight and obesity. Research to test cross-continentally labelled serving size format changes within experimental and natural settings (e.g., at home) are needed. In addition, tailored, comprehensive and serving-size-specific food literacy initiatives need to be evaluated to provide recommendations for effective serving size labelling. This is required to ensure the correct understanding of nutritional content, as well as informing food choices and consumption, for both core foods and discretionary foods.

Image-based food portion size estimation using a smartphone without a fiducial marker

OBJECTIVE

Current approaches to food volume estimation require the person to carry a fiducial marker (e.g. a checkerboard card), to be placed next to the food before taking a picture. This procedure is inconvenient and post-processing of the food picture is time-consuming and sometimes inaccurate. These problems keep people from using the smartphone for self-administered dietary assessment. The current bioengineering study presents a novel smartphone-based imaging approach to table-side estimation of food volume which overcomes current limitations.

DESIGN

We present a new method for food volume estimation without a fiducial marker. Our mathematical model indicates that, using a special picture-taking strategy, the smartphone-based imaging system can be calibrated adequately if the physical length of the smartphone and the output of the motion sensor within the device are known. We also present and test a new virtual reality method for food volume estimation using the International Food Unit™ and a training process for error control.

RESULTS

Our pilot study, with sixty-nine participants and fifteen foods, indicates that the fiducial-marker-free approach is valid and that the training improves estimation accuracy significantly (P0·05).

CONCLUSIONS

Elimination of a fiducial marker and application of virtual reality, the International Food Unit™ and an automated training allowed quick food volume estimation and control of the estimation error. The estimated volume could be used to search a nutrient database and determine energy and nutrients in the diet.