Consumers' practical understanding of healthy food choices: a fake food experiment

Food choices for weight loss: what dietary strategies would people use?

Previous observational research showed that one of the most common strategies used to lose weight is to avoid or restrict the consumption of specific food items. However, the question of how people behave and implement strategies in actual decision-making situations involving food choices for weight loss purposes remains inconclusive. This experimental study using a food buffet aimed to examine people's different dietary strategies and motives for selecting foods for an entire day for weight loss purposes compared with a normal-day (ND) food selection. A total of 111 participants (55 % women) had to choose foods for both a ND and a weight loss day (WLD) (within-study design). Kilocalories and nutrients were calculated based on the weights of the foods selected, and food choice motives were assessed using a questionnaire. The results showed that for weight loss purposes, the participants selected more vegetables (both sexes) and unsweetened beverages (only men) while reducing their choices of high-fat and high-energy products (both sexes). Participants' food choices in both conditions (ND and WLD) differed from the official nutrition recommendations. They chose less carbohydrates and fibres and more fat and sugar than recommended. Health, kilocalories and nutrient content (carbohydrates, sugar, fat and protein) were more important food choice motives for weight loss purposes than for a ND food selection, while taste became less important. In conclusion, the participants appeared to be well capable of implementing several appropriate dietary strategies. Further research is needed to explore strategies to help them maintain these dietary changes over the long term.

The specially designed nudging tableware promotes healthy food choices: Evidence from a randomized crossover trial in normal-weight young adults

PURPOSE

To evaluate the effects of the specially designed nudging tableware, including a plate and bowl, on individual food choices in normal-weight young adults and preliminarily explore its mechanisms. We hypothesized that the toolset could increase the choice of vegetables and decrease that of rice.

METHODS

A randomized, single-blind, two-period crossover trial was carried out among 40 normal-weight university students in China. All subjects completed two buffets separated by an interval of one week, wearing the eye tracker. Vegetable choice, evaluated through the proportion of vegetables, was the primary outcome, and the weight of vegetables and rice were the secondary outcomes. The mechanisms of the decision-making process were preliminarily explored through eye tracking.

RESULTS

The usage of the nudging tableware significantly increased the proportion of vegetables and decreased the amount of rice taken (P<0.05), while insignificantly increased the weight of vegetables (P = 0.079). Eye tracking shows that the nudging plate significantly prolonged the food-choosing process and fixation duration on vegetables (P<0.05), and the latter was positively correlated to the increased quantity of vegetables while using the nudging plate (r = 0.493, P<0.01).

CONCLUSION

The specially designed nudging tableware might be an effective and practical tool to promote the choice of less rice and more vegetables. Mechanisms behind this change might include automatic and unconscious processes with the inconspicuously smaller capacity of the bowl and larger portion size of the vegetable segment, and increased attention triggered by the vegetable patterns and larger green underpainting.

Effect of nutrient, processing and hedonic claims on food-related perceptions: An experimental online study in Brazil and Germany

Prior studies on perceived healthiness of foods have often compared nutrient and hedonic claims, neglecting comparisons to a control condition. The effect of food claims focusing on the food processing level has received considerably less research attention, although food processing has been included in dietary guidelines in Brazil. Thus, the present study aimed to explore the effect of a control and processing claim, additionally to the effects of a nutrient. and hedonic claim, on perceptions related to a food item typically considered "less healthy" (chocolate cake). We further compared these effects between Brazil and Germany, a country where food processing is currently not included in dietary guidelines. A total of 634 lay adults were recruited in a cross-sectional online study and randomised to see the photo of a piece of cake with one of the four different claim conditions and to report their health-related perceptions of the cake. The main analyses included two-way ANCOVAs (4 claims x 2 countries) for each dependent variable controlled for gender, age and level of hunger; followed by post hoc tests. Overall, results revealed that in both countries, the claims highlighting nutrients or processing aspects rendered the perceptions of the cake healthier compared to the control claim. These effects were more pronounced among Brazilian than among German participants. Food-related perceptions mostly did not differ between the hedonic and control claim and did not differ at all between the nutrient and processing claims. In conclusion, it is noteworthy that, even for an inherently considered "less healthy food item" (chocolate cake) nutrient and processing claims increase healthiness perceptions. While our findings may imply that in both countries lay people are highly susceptible to nutrient claims, food processing aspects seem to be similarly relevant.

Promoting and disseminating consistent and effective nutrition messages: challenges and opportunities

Nutrition messages are a central part of policy making as well as communication via product information, advertising, healthcare advice and lifestyle campaigns. However, with amplified information (and misinformation) from a growing number of sources, inconsistent and conflicting food landscapes, and limited engagement from the public, nutrition messaging tensions have become more accentuated than previously. In this review, we focus on the challenges facing those wishing to effect dietary change through communication; and identify opportunities and future research questions. Beginning with a new working definition and taxonomy for the term ‘nutrition message’, we consider the evolution of public health nutrition messages from the past century and discuss which types of messages may be more effective. We then turn to the challenges of implementation and highlight specific barriers to recipients' understanding and change. While the evidence has many gaps and there is a need for systematic evaluation of nutrition messages, research indicates that recipients are more likely to act on fewer messages that provide clear benefits and which resonate with their perceived health needs, and which are relatively straightforward to implement. Effectiveness may be improved through consideration of how nutrition messages can be designed to complement key non-health drivers of food choice (taste, cost) and societal/cultural norms. Consistency can be achieved by aligning the wider food and messaging environment to desired public health actions; that is by ensuring that retail settings provide and signpost healthier choices, and that mass media nutrition messages work with, not against, public health advice.

High-protein diet associated with resistance training reduces cardiac TNF-α levels and up-regulates MMP-2 activity in rats

The consumption of high-protein diets (HPD) is associated with resistance training (RT) due to effects on metabolism. However, little is known about these effects on cardiac tissue. This study aimed to investigate effects of HPD and RT on cardiac biomarkers. 18 rats were divided into normo-protein (NPD), and HPD groups: NPD-Control, NPD-RT, HPD-Control, and HPD-RT. Interleukin-6 (IL-6), tumour necrosis factor alpha (TNF-a), nitric oxide (NO), activity of metalloproteinase-2 (MMP-2), and vascular factor (VEGF) were analysed. RT was effective in regulating body weight, increasing strength, and reducing food consumption (p < .05). HPD induces higher levels of interleukin 6 (p = .0169), and lowers NO (p < .0001). When associated with RT, the HPD decreases levels of tumour necrosis factor alpha, while enhances NO, and MMP activity (p < .05). The association of RT with HDP decreases inflammatory parameters and indicates an enhancement in the molecular parameters of cardiac tissue.

School and community drivers of child diets in two Arab cities: The SCALE protocol and innovative tools to assess children’s food environments

Background

In the context of the rapid nutrition transition experienced by middle-income countries of the Arab region, children and adolescent’s food choices and dietary behaviors are early risk factors for the development of non-communicable diseases. Assessment of factors influencing food choices among this age group is challenging and is usually based on self-reported data, which are prone to information and recall bias. As the popularity of technologies and video gaming platforms increases, opportunities arise to use these tools to collect data on variables that affect food choice, dietary intake, and associated outcomes. This protocol paper describes the SCALE study (School and community drivers of child diets in Arab cities; identifying levers for intervention) which aims to explore the environments at the level of households, schools and communities in which children’s food choices are made and consequently identify barriers and enablers to healthy food choices within these environments.

Methods

Field studies are being conducted in primary schools, among children aged 9–12 years, in Greater Beirut, Lebanon and Greater Tunis, Tunisia. A stratified random sample of 50 primary schools (public and private) are selected and 50 children are randomly selected from grades 4-5-6 in each school. The study includes surveys with children, parents/caregivers, school directors, teachers, and nutrition/health educators to assess individual diets and the contextual factors that influence children’s food choices. Innovative locally adapted tools and methods such as game-based choice experiments, wearable cameras and neighborhood mapping are used to describe the environments in which children’s food choices are made.

Discussion

The SCALE study will generate contextual knowledge on factors in school and neighborhood environments that influence child dietary behaviors and will inform multi-level interventions and policies to address childhood malnutrition (under-and over-nutrition). By integrating methods from various disciplines, including economics, data science, nutrition, and public health and by considering factors at various levels (home, school, and neighborhood), the study will identify levers for intervention with the potential to improve children’s dietary behaviors. This will help fill existing gaps in research on food systems and consequently guide positive change in Lebanon and Tunisia, with the potential for replicability in other contexts.

The effects of nutrition and health claims on the nutrient composition of single and subsequent meal servings

Nutrition and health claims (NHCs) can help individuals make better food choices. While NHCs have been found to influence consumer perceptions and consumption, there has been less focus on how claims influence the nutritional composition of servings. There has also been little attention paid to longer term or compensatory effects of claims on subsequent food selection. This manuscript details two studies considering these matters. Study 1 (n = 60) was a within-subjects experiment to measure the impact of NHCs on food selection and nutritional composition at single meal servings. Participants served from three fake food buffet meal stations (breakfast, hot meal, snacks) with NHCs present or absent. Study 2 (n = 55) was a within-subjects experiment to examine the impact of NHCs on food selection and nutritional composition at a subsequent meal. Participants served from a fake food buffet breakfast with or without NHCs followed by a lunch without NHCs. In study 1, while results varied for different meals, the presence of claims was found to significantly reduce the amount of energy, fat, saturated fat, sugar, carbohydrates, and sodium, and increase the amount of protein in meals that were served. Results for fibre were mixed. In addition, NHCs increased the quantity of food served in the snacks condition. There was no evidence of claims at breakfast impacting the nutritional composition of subsequent lunch servings in study 2. Despite claims potentially increasing serving quantities, the nutritional composition of chosen servings was more encouraging and claims may help individuals to meet recommended nutritional daily guidelines. These findings have wider implications in terms of government policy, food reformulation, and the continuing debate around the use of nutrient profiling regulations for products carrying claims.

The Use of Portion Control Plates to Promote Healthy Eating and Diet-Related Outcomes: A Scoping Review

The role of portion control plates in achieving healthy diets is unclear. The aim of this scoping review was to systematically map findings from peer reviewed and grey literature to provide evidence for the use of portion control plates to promote healthy eating and nutrition-related knowledge in children and adults. A secondary aim was to review the design characteristics of portion control plates. The search was conducted in four databases, including Medline, CINAHL, Embase, and PsycInfo, and grey literature sources following the PRISMA scoping review guidelines. A total of 22 articles comprising 23 intervention studies and 8 from grey literature were included. It was found that the various two-dimensional and three-dimensional portion control plates examined were effective tools for better portion size selection in healthy children and adults. Most portion control plates dedicated half the plate to vegetables, a quarter to protein, and a quarter to carbohydrates. The use of portion control plates in nutrition interventions appears to promote weight loss among those with overweight and obesity and/or type 2 diabetes. However, portion control plates were mostly used as part of multicomponent interventions and the effectiveness of the portion control plate as a stand-alone educational resource or portion control tool alone was uncertain. Further interventional research is indicated to investigate portion plates as tools to improve dietary behaviours and food consumption at the population level.

High animal protein diet and gut microbiota in human health

The role of the intestinal flora in health and disease has become a research hotspot. Compared with carbohydrates and fats, proteins are metabolized primarily by microbial fermentation in the intestine. The production of protein fermentation products and metabolites depends on the composition, diversity, and metabolism of the gut microbiota. Several protein fermentation products, including indoles, phenols, polyamines, hydrogen sulfide (H₂S), amines, and carnitine, are toxic. This study analyzes the relationship between high-protein diets (HPDs), the intestinal microbiota, and human health and disease. Long-term HPDs increase the risk of intestinal diseases, type 2 diabetes (T2DM), obesity, central nervous system (CNS) diseases, and cardiovascular diseases (CVD) by producing toxic metabolites in the colon, including amines, H₂S, and ammonia. Short-term HPDs have little effect on the metabolism of healthy individuals under 65 years old. However, meeting the protein requirements of individuals over 65 years old using HPDs is more challenging. The adverse effects of HPDs on athletes are minimal. Natural compounds (plant extracts, whose main constituents are polysaccharides and polyphenols), prebiotics, probiotics, and regular physical exercise improve gut dysbiosis and reduce disease risk.

Consumers' Motives for Eating and Choosing Sweet Baked Products: A Cross-Cultural Segmentation Study

This study aimed to examine consumers' motives for eating and choosing sweet baked products (SBPs). A cross-cultural segmentation study on a South African (SA) and Swiss population sample (n = 216), was implemented using the Motivation for Eating Scale (MFES) and the Food Choice Questionnaire (FCQ). Cluster analyses provided three consumer segments for each population sample: the balanced and the frequenters for both countries, the deniers for SA, and the health conscious for Switzerland. South Africans liked SBPs more than the Swiss respondents, however the Swiss sample consumed SBPs more often. Environmental and physical eating were the most relevant motives when eating SBPs for the SA and Swiss group, respectively. For both samples, sensory appeal was the deciding factor when choosing SBPs. Cross-cultural studies of food choices are important tools that could help improve the current understanding of factors that influence the eating behavior of ultra-processed foods to promote healthy food choices through local and global perspectives. This paper highlights that more research is needed on consumers' motives for choosing and eating ultra-processed foods in order to develop specific integrative cultural exchange actions or intervention strategies to solve the obesity issue.

A word of caution against excessive protein intake

Dietary protein is crucial for human health because it provides essential amino acids for protein synthesis. In addition, dietary protein is more satiating than carbohydrate and fat. Accordingly, many people consider the protein content when purchasing food and beverages and report 'trying to eat more protein'. The global market for protein ingredients is projected to reach approximately US$90 billion by 2021, largely driven by the growing demand for protein-fortified food products. This Perspective serves as a caution against the trend of protein-enriched diets and provides an evidence-based counterpoint that underscores the potential adverse public health consequences of high protein intake.

Boosting healthy food choices by meal colour variety: results from two experiments and a just-in-time Ecological Momentary Intervention

BACKGROUND

Dietary guidelines typically specify rather complex goals and indicators for healthy food choices, such as nutrient and energy content patterns. However, translating these complex goals into practice in real life is often a major obstacle for many people. The present studies propose an intervention strategy for boosting healthy food choices by prompting consumers at a meaningful moment with a simple behavioural trigger, that is to eat a colourful lunch. Effectivity and feasibility of this intervention strategy were tested in two laboratory experiments and one real-life, smartphone-based Ecological Momentary Intervention.

METHODS

In Studies 1 and 2, 83 / 42 participants self-served four meals (colourful, typical, healthy, and low-calorie) / three meals (colourful, typical, and varied) from a Fake Food Buffet. In Study 3, 80 participants recorded images of 1,210 lunch meals over a period of 3 weeks using mobile visual food recording. In the second week, participants additionally received a daily smartphone prompt to eat a colourful lunch. In all studies, participants were asked to rate the prompts' feasibility.

RESULTS

Prompting participants to eat a colourful meal increased the proportion of healthy foods consumed compared to typical meals in all three studies. In Studies 1 and 2, colourful meals contained more fruit and vegetables, while in Study 3 the prompt increased vegetable consumption. Furthermore, participants evaluated colourful meals to be the tastiest (Study 1) and most pleasant, and reported that the prompt was easy to follow and act upon.

CONCLUSIONS

Results suggest that prompting individuals to eat colourful meals is a promising strategy to facilitate healthy food choices in daily life.

TRIAL REGISTRATION

German Clinical Trials Register, DRKS00017552 (Study 3; retrospectively registered on 24th June 2019).

Best practices in nutrition science to earn and keep the public's trust

Public trust in nutrition science is the foundation on which nutrition and health progress is based, including sound public health. An ASN-commissioned, independent Advisory Committee comprehensively reviewed the literature and available public surveys about the public's trust in nutrition science and the factors that influence it and conducted stakeholder outreach regarding publicly available information. The Committee selected 7 overlapping domains projected to significantly influence public trust: 1) conflict of interest and objectivity; 2) public benefit; 3) standards of scientific rigor and reproducibility; 4) transparency; 5) equity; 6) information dissemination (education, communication, and marketing); and 7) accountability. The literature review comprehensively explored current practices and threats to public trust in nutrition science, including gaps that erode trust. Unfortunately, there is a paucity of peer-reviewed material specifically focused on nutrition science. Available material was examined, and its analysis informed the development of priority best practices. The Committee proposed best practices to support public trust, appropriate to ASN and other food and nutrition organizations motivated by the conviction that public trust remains key to the realization of the benefits of past, present, and future scientific advances. The adoption of the best practices by food and nutrition organizations, such as ASN, other stakeholder organizations, researchers, food and nutrition professionals, companies, government officials, and individuals working in the food and nutrition space would strengthen and help ensure earning and keeping the public's continued trust in nutrition science.

Mixed deep learning and natural language processing method for fake-food image recognition and standardization to help automated dietary assessment

OBJECTIVE

The present study tested the combination of an established and a validated food-choice research method (the 'fake food buffet') with a new food-matching technology to automate the data collection and analysis.

DESIGN

The methodology combines fake-food image recognition using deep learning and food matching and standardization based on natural language processing. The former is specific because it uses a single deep learning network to perform both the segmentation and the classification at the pixel level of the image. To assess its performance, measures based on the standard pixel accuracy and Intersection over Union were applied. Food matching firstly describes each of the recognized food items in the image and then matches the food items with their compositional data, considering both their food names and their descriptors.

RESULTS

The final accuracy of the deep learning model trained on fake-food images acquired by 124 study participants and providing fifty-five food classes was 92·18 %, while the food matching was performed with a classification accuracy of 93 %.

CONCLUSIONS

The present findings are a step towards automating dietary assessment and food-choice research. The methodology outperforms other approaches in pixel accuracy, and since it is the first automatic solution for recognizing the images of fake foods, the results could be used as a baseline for possible future studies. As the approach enables a semi-automatic description of recognized food items (e.g. with respect to FoodEx2), these can be linked to any food composition database that applies the same classification and description system.

Consumers' health-related perceptions of bread - Implications for labeling and health communication

There is a wide variety of commercial bread types and the present study identifies potential pitfalls in consumer evaluations of bread from a health perspective. The aim is to describe consumers' health-related perceptions of bread by exploring which health-related quality attributes consumers associate with bread and whether there are differences with regard to age, gender and education level. A postal and web-based sequential mixed-mode survey (n = 1134, 62% responded online and 38% by paper) with open-ended questions and an elicitation task with pictures of commercial breads were used. Responses were content analyzed and inductively categorized. Three fourths (n = 844) knew of breads they considered healthy; these were most commonly described using terms such as "coarse," "whole grain," "fiber rich," "sourdough," "crisp," "less sugar," "dark," "rye," "seeds," "a commercial brand," "homemade" and "kernels." The breads were perceived as healthy mainly because they "contain fiber," are "good for the stomach," have good "satiation" and beneficial "glycemic properties." The frequency of several elicited attributes and health effects differed as a function of age group (18-44 vs. 45-80 years), gender and education level group (up to secondary education vs. university). Difficulties identifying healthy bread were perceived as a barrier for consumption especially among consumers with a lower education level. Several of the health effects important to consumers cannot be communicated on food packages and consumers must therefore use their own cues to identify these properties. This may lead to consumers being misled especially if a bread is labeled e.g., as a sourdough bread or a rye bread, despite a low content.

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

Background

Portion size education tools, aids and interventions can be effective in helping prevent weight gain. However consumers have difficulties in estimating food portion sizes and are confused by inconsistencies in measurement units and terminologies currently used. Visual cues are an important mediator of portion size estimation, but standardized measurement units are required.

In the current study, we present a new food volume estimation tool and test the ability of young adults to accurately quantify food volumes. The International Food Unit™ (IFU™) is a 4x4x4 cm cube (64cm³), subdivided into eight 2 cm sub-cubes for estimating smaller food volumes. Compared with currently used measures such as cups and spoons, the IFU™ standardizes estimation of food volumes with metric measures. The IFU™ design is based on binary dimensional increments and the cubic shape facilitates portion size education and training, memory and recall, and computer processing which is binary in nature.

Methods

The performance of the IFU™ was tested in a randomized between-subject experiment (n = 128 adults, 66 men) that estimated volumes of 17 foods using four methods; the IFU™ cube, a deformable modelling clay cube, a household measuring cup or no aid (weight estimation). Estimation errors were compared between groups using Kruskall-Wallis tests and post-hoc comparisons.

Results

Estimation errors differed significantly between groups (H(3) = 28.48, p < .001). The volume estimations were most accurate in the group using the IFU™ cube (Mdn = 18.9%, IQR = 50.2) and least accurate using the measuring cup (Mdn = 87.7%, IQR = 56.1). The modelling clay cube led to a median error of 44.8% (IQR = 41.9). Compared with the measuring cup, the estimation errors using the IFU™ were significantly smaller for 12 food portions and similar for 5 food portions. Weight estimation was associated with a median error of 23.5% (IQR = 79.8).

Conclusions

The IFU™ improves volume estimation accuracy compared to other methods. The cubic shape was perceived as favourable, with subdivision and multiplication facilitating volume estimation. Further studies should investigate whether the IFU™ can facilitate portion size training and whether portion size education using the IFU™ is effective and sustainable without the aid. A 3-dimensional IFU™ could serve as a reference object for estimating food volume.

Electronic supplementary material

The online version of this article (10.1186/s12966-017-0583-y) contains supplementary material, which is available to authorized users.

Back-of-pack information in substitutive food choices: A process-tracking study in participants intending to eat healthy

People are increasingly aware of the positive effects of a healthy diet. Concurrently, daily food consumption decisions - choices about both the quality and quantity of food that is ingested - are steered more by what consumers consider healthy. Despite the increased aim to eat healthier, however, consumers often do not read or incorrectly interpret on-pack nutrition information, resulting in suboptimal food choices in terms of health. This study aims to unravel the determinants of such inadvertent food choices from these consumers. In an online process-tracking study, we measured the actual usage of available back-of-pack nutrition information during substitutive food choices made by 240 participants who had the intention to eat healthy. Using mouse-tracking software in a computerized task in which participants had to make dichotomous food choices (e.g., coconut oil or olive oil for baking), we measured the frequency and time of nutritional information considered. Combined with demographic and psychosocial data, including information on the level of intention, action planning, self-efficacy, and nutrition literacy, we were able to model the determinants of inadvertent unhealthy substitutive food choices in a sequential multiple regression (R² = 0.40). In these consumers who intended to eat healthy, the quantity of obtained nutrition information significantly contributed as an associative factor of the percentage of healthy food choices made. Moreover, the level of correct answers in a nutrition literacy test, as well as taste preferences, significantly predicted the percentage of healthier choices. We discuss that common psychosocial determinants of healthy behavior, such as intention, action planning, and self-efficacy, need to be augmented with a person's actual reading and understanding of nutrition information to better explain the variance in healthy food choice behavior.

ServAR: An augmented reality tool to guide the serving of food

Background

Accurate estimation of food portion size is a difficult task. Visual cues are important mediators of portion size and therefore technology-based aids may assist consumers when serving and estimating food portions. The current study evaluated the usability and impact on estimation error of standard food servings of a novel augmented reality food serving aid, ServAR.

Methods

Participants were randomised into one of three groups: 1) no information/aid (control); 2) verbal information on standard serving sizes; or 3) ServAR, an aid which overlayed virtual food servings over a plate using a tablet computer. Participants were asked to estimate the standard serving sizes of nine foods (broccoli, carrots, cauliflower, green beans, kidney beans, potato, pasta, rice, and sweetcorn) using validated food replicas. Wilcoxon signed-rank tests compared median served weights of each food to reference standard serving size weights. Percentage error was used to compare the estimation of serving size accuracy between the three groups. All participants also performed a usability test using the ServAR tool to guide the serving of one randomly selected food.

Results

Ninety adults (78.9% female; a mean (95%CI) age 25.8 (24.9–26.7) years; BMI 24.2 (23.2–25.2) kg/m²) completed the study. The median servings were significantly different to the reference portions for five foods in the ServAR group, compared to eight foods in the information only group and seven foods for the control group. The cumulative proportion of total estimations per group within ±10%, ±25% and ±50% of the reference portion was greater for those using ServAR (30.7, 65.2 and 90.7%; respectively), compared to the information only group (19.6, 47.4 and 77.4%) and control group (10.0, 33.7 and 68.9%). Participants generally found the ServAR tool easy to use and agreed that it showed potential to support optimal portion size selection. However, some refinements to the ServAR tool are required to improve the user experience.

Conclusions

Use of the augmented reality tool improved accuracy and consistency of estimating standard serve sizes compared to the information only and control conditions. ServAR demonstrates potential as a practical tool to guide the serving of food. Further evaluation across a broad range of foods, portion sizes and settings is warranted.