Addressing nutritional issues and eating behaviours among university students: a narrative review.

University life is a critical period for establishing healthy eating habits and attitudes. However, university students are at risk of developing poor eating habits due to various factors, including economic conditions, academic stress and lack of information about nutritional concepts. Poor diet quality leads to malnutrition or overnutrition, increasing the risk of preventable diseases. Food environments on university campuses also play a significant role in shaping the dietary habits of students, with the availability of and accessibility to healthy food options being important factors influencing food choices and overall diet quality. Disordered eating habits and body dissatisfaction are prevalent among university students and can lead to eating disorders. Income and living arrangements also influence dietary habits, with low household income and living alone being associated with unhealthy eating habits. This study is a narrative review that aimed to address nutritional issues and eating behaviours, specifically among university students. We investigated the eating behaviours of university students, including their dietary patterns, food choices and food environments. The objective of this review was to provide insights into the nutritional issues and eating behaviours of university students, with the aim of identifying target areas for intervention to improve the overall health and wellbeing among college students. University food environments need to be restructured to promote healthy eating, including the availability, accessibility, affordability and labelling of healthy foods, and policies to limit the availability of unhealthy foods and drinks on campus.

Effects of traffic light labelling and increased healthy range on beverage choices from vending machines.

OBJECTIVE: To test whether traffic light labels and an increased range of healthy beverages, individually and in combination, can increase healthy beverage choices from vending machines. DESIGN: Two studies (n 558, 420) tested whether the provision of traffic light labels (green, amber and red) and an increased range of healthy beverages (from 20 % to 50 % green options), individually and in combination, could increase healthy beverage choices from a digital vending machine display. The studies used a between-subjects experimental design, and a hypothetical beverage choice, a limitation when considering real-world applicability. SETTING: Both studies utilised an online Qualtrics survey that featured a digital vending machine display. PARTICIPANTS: Both studies (n 558, 420) consisted of university students from Flinders University and individuals from a survey recruitment service. RESULTS: Featuring traffic lights did not significantly influence beverage choices (P = 0·074), while increasing the healthy range (P = 0·003, OR = 3·27), and the combination of both, did significantly increase healthier beverage choices (P < 0·001, OR = 4·83). CONCLUSIONS: The results suggest that the traffic light system and increased healthy range are not maximally effective when used on their own, and benefit greatly when combined, to increase healthy beverage choices. It was suggested that the provision of traffic light labels supplied the necessary nutritional information, and the increased healthy range offered greater opportunity to act in accordance with that information. In so doing, the present findings offer a promising pathway for reducing unhealthy beverage consumption.

Efficient Defect Detection of Rotating Goods under the Background of Intelligent Retail.

Dynamic visual vending machines are rapidly growing in popularity, offering convenience and speed to customers. However, there is a prevalent issue with consumers damaging goods and then returning them to the machine, severely affecting business interests. This paper addresses the issue from the standpoint of defect detection. Although existing industrial defect detection algorithms, such as PatchCore, perform well, they face challenges, including handling goods in various orientations, detection speeds that do not meet real-time monitoring requirements, and complex backgrounds that hinder detection accuracy. These challenges hinder their application in dynamic vending environments. It is crucial to note that efficient visual features play a vital role in memory banks, yet current memory repositories for industrial inspection algorithms do not adequately address the problem of location-specific feature redundancy. To tackle these issues, this paper introduces a novel defect detection algorithm for goods using adaptive subsampling and partitioned memory banks. Firstly, Grad-CAM is utilized to extract deep features, which, in combination with shallow features, mitigate the impact of complex backgrounds on detection accuracy. Next, graph convolutional networks extract rotationally invariant features. The adaptive subsampling partitioned memory bank is then employed to store features of non-defective goods, which reduces memory consumption and enhances training speed. Experimental results on the MVTec AD dataset demonstrate that the proposed algorithm achieves a marked improvement in detection speed while maintaining accuracy that is comparable to state-of-the-art models.

Effectiveness of visual nudges for encouraging healthier beverage choices from vending machines.

ISSUES ADDRESSED: Research suggests visual nudging techniques can subtly encourage healthier consumption. Two experiments explored the effect of four visual primes for nudging drink choices from a vending machine display. METHODS: Participants (17-25 years) were randomly assigned to view vending machine advertising posters containing pictorial nudges of water, soft drink, general health (runner), or a text-only control, for nudging vending machine choices. Participants then selected an item from a vending machine display containing drinks only (Experiment 1; n = 164), or both drinks and snack foods (Experiment 2, n = 684). RESULTS: In both experiments, nudging condition predicted beverage choice. Specifically, the water image nudged healthier beverage choices in both experiments. However, there was no effect on food choice in Experiment 2. Furthermore, in both experiments, liking and habitual consumption of chosen items were also significant predictors of choice, but condition predicted beverage choice over and above these. CONCLUSION: A water prime may be an effective means of encouraging healthier beverage choices in a vending machine environment. SO WHAT?: Findings have the potential to inform strategies for encouraging healthier beverage choices from vending machine environments.

Evaluation of an experiment to increase availability of healthier snack foods in vending machines situated within English sports facilities.

OBJECTIVE: To evaluate the impact of increased availability of healthier options on purchasing of different types of vending snack products sold in English leisure (sports) centres. DESIGN: An evaluation of an intervention using pre-post methods and interrupted time series analysis. Products within the vending machines were altered over three phases to increase the availability of healthier options, using agreed nutrition criteria - Government Buying Standards for Food and Catering Services (GBSF) for England - as a guide, as well as product availability. The primary outcome was the change in mean weekly purchased energy between the first and third phase. Secondary outcomes included changes by phase and by week in weekly number of purchases, fats, sugars and salt for all products combined and by individual product categories. SETTING: Fifteen sports centres in the city of Leeds, West Yorkshire, UK. PARTICIPANTS: Snack products sold in eighteen vending machines. RESULTS: Energy purchased reduced from baseline to phase 2, for all product categories combined, by 47·25 MJ (95 % CI (-61·22, -33·27)) per machine and by 279 kJ, (95 % CI (-325, -266)) per product unit. There were reductions in most nutrients purchased in all individual product categories except chocolate confectionery. Nutrients per product unit decreased for all product categories except saturated fat in chocolate confectionery. Minimal underlying trends in the baseline phase were identified, indicating changes in outcomes were likely to be due to the intervention. CONCLUSIONS: Introducing standards to increase availability of healthier snack products in vending machines is feasible without substantially affecting sales.

"There's absolutely no downside to this, I mean, except community opposition:" A qualitative study of the acceptability of vending machines for harm reduction.

BACKGROUND: Vending machines for harm reduction (VMHR) are an innovative approach to deliver life-saving materials, information, and treatment for hard-to-reach populations, particularly for persons who inject drugs. The current study explores stakeholders' perspectives on the feasibility and acceptability of VMHR in Philadelphia. METHODS: From October 2021 to February 2022, we conducted 31 semi-structured interviews with potential end users, staff, and leadership at a local federally qualified health center, and community members. Trained coders extracted themes from interview transcripts across four key domains: materials and logistics, location, access, and community introduction. RESULTS: Interviewees from all stakeholder groups endorsed using VMHR to provide supplies for wound care, fentanyl test strips, naloxone, and materials to connect individuals to treatment and other services. Dispensing syringes and medications for opioid use disorder were commonly endorsed by health center staff but were more controversial among potential end users. Even within stakeholder groups, views varied with respect to where to locate the machines, but most agreed that the machine should be placed in the highest drug use areas. Across stakeholder groups, interviewees suggested several strategies to introduce and gain community acceptance of VMHR, including community education, one-on-one conversations with community members, and coupling the machine with safe disposal of syringes and information to link individuals to treatment. CONCLUSIONS: Stakeholders were generally receptive to VMHR. The current study findings are consistent with qualitative analyses from outside of the USA and contribute new ideas regarding the anticipated community response and best methods for introducing these machines to a community. With thoughtful planning and design, VMHR could be a feasible and acceptable modality to reduce death and disease transmission associated with the opioid and HIV epidemics in cities like Philadelphia.

A Real-Time Application for the Analysis of Multi-Purpose Vending Machines with Machine Learning.

With the development of mobile payment, the Internet of Things (IoT) and artificial intelligence (AI), smart vending machines, as a kind of unmanned retail, are moving towards a new future. However, the scarcity of data in vending machine scenarios is not conducive to the development of its unmanned services. This paper focuses on using machine learning on small data to detect the placement of the spiral rack indicated by the end of the spiral rack, which is the most crucial factor in causing a product potentially to get stuck in vending machines during the dispensation. To this end, we propose a k-means clustering-based method for splitting small data that is unevenly distributed both in number and in features due to real-world constraints and design a remarkably lightweight convolutional neural network (CNN) as a classifier model for the benefit of real-time application. Our proposal of data splitting along with the CNN is visually interpreted to be effective in that the trained model is robust enough to be unaffected by changes in products and reaches an accuracy of 100%. We also design a single-board computer-based handheld device and implement the trained model to demonstrate the feasibility of a real-time application.

Developing, Implementing, and Evaluating a Campus-Wide Pharmacy Vending Machine Program.

Lack of access to affordable, accessible, over-the-counter medications and health-related items affects school attendance, academic performance, and individual health. Increasing access through innovations, such as Pharmacy Vending Machines (PhVMs), may address the burdens students face in university settings. In January 2021, two PhVMs were placed on Purdue University's campus to increase access to affordable and dependable 24/7 family planning items, cold/flu remedies, and other popular over-the-counter pharmaceuticals. Based on the success of the initiative and growing student body, the program was expanded to include two additional machines in August 2021. In this article, we detail how Purdue University planned, implemented, and evaluated a campus-wide PhVM program, which was an interdisciplinary collaboration across students, faculty, and staff in the College of Health and Human Sciences and College of Pharmacy. Pharmaceutical product availability in convenient vending machines dispersed throughout a campus contributes to a solution for the increasing demand for health products among consumers in large geographic areas.

"Leave us alone": 'right to the city' of street vendors along Main North 1 Road, Maseru, Lesotho.

This article explores the lived daily experiences of street vendors operating along the Main North 1 Road in the CBD of Maseru, Lesotho. This exploration considers how street vendors access and negotiate a claim for the right to the street. The challenges confronting these vendors in their daily hustling, including COVID-19 restrictions, are also examined. A narrative inquiry research design informs this article with data collected from interviews with purposively selected street vendors from Maseru. This primary data was triangulated with document analysis to increase the validity of the findings. The findings highlight strategies employed by vendors in Maseru that include integrating with the formal enterprises, diversifying their trades, resisting and frustrating certain decisions by the local authorities, and contributing to urban blight. A framework for interrogating and understanding street vending and its nuances is postulated based on the findings from Maseru. The article strongly appeals to the authorities to find more benign ways of integrating street vending into the production of cities.

Vending machine backgrounds: nudging healthier beverage choices.

Soft drink overconsumption is a growing public health concern. The present research investigated whether priming nudges could decrease soft drink choices from a vending machine. We compared the effect of six vending machine wraps (Mount Franklin ™ logo, Coca-Cola™ logo, picture of water, picture of soft drink, blue, red) on beverage choice against a black (control) computerised vending machine display. In two studies, young adult participants (17 - 25 years) were recruited from [removed for blind review] (Study 1, n = 142, Study 2, n = 232). Participants were randomly allocated to choose a beverage from one of the wrap conditions. They also rated how much the beverage was liked and how often it was consumed (Study 1), or rated the refreshing value, healthiness, taste, and energy of each beverage in the vending machine (Study 2). We predicted that wraps referencing water would produce healthier choices and those referencing soft drink would result in unhealthier choices. Contrary to these predictions, the type of vending machine wrap did not significantly influence beverage choice in Study 1. However, viewing the black vending machine wrap resulted in significantly more caffeine-based selections in Study 2. Other significant predictors of the choice of beverage were how often the beverages were consumed and how much they were liked (Study 1), as well as their perceptions of the taste, healthiness and refreshing value (Study 2). The finding that the black vending machine produced more caffeine-based beverage choices demonstrates, in principle, that color-based priming nudges could influence beverage choices.

Quantitative versus qualitative risk assessment of meat and its products: what is feasible for Sub-Saharan African countries?

Prevalent risks in meat value-chains of sub-Saharan African (SSA) countries are increasingly attributed to microbial rather than chemical hazards. Resource constraints and lack of capacity has limited the utilization of risk assessment tools in the instituting of food controls to mitigate the risks. The review sought to bring to light the focus of risk assessment studies in SSA while generating evidence of feasible options to further the contribution of this component in risk mitigation. The informal street vending sector emerges as a priority in the meat value chain with a vendor population that are unwilling to abandon it. Campylobacter and Staphylococcus aureus are prevalent risks that have bedeviled this sector. However, limited risk assessment studies with capacity to inform proper food controls for the sector have been done. Evidence in place indicate that the incorporation of qualitative aspects in quantitative approaches serve as less-costly and effective ways of generating risk estimates. Limitations of capacity and gaps in epidemiological data are also circumvented. Considering that the street-vending sector is robust and its dynamics of operation are not fully in the picture of policy actors; incorporation of a participatory approach that combines qualitative and quantitative aspects of risk assessment is highly recommended.

Meal-to-meal and day-to-day macronutrient variation in an ad libitum vending food paradigm.

BACKGROUND: Theory posits that macronutrient intake is regulated by protein consumption and adequate intake of protein results in consumption of less carbohydrates and fat. The current study investigates the effect of protein intake on calorie and macronutrient content using an ad libitum vending machine paradigm. METHODS: Healthy volunteers (n = 287; 177 m; Age = 36 ± 11; BMI = 32 ± 8) were admitted to our clinical research unit. Macronutrient meal content (grams) and energy intake (Kcal) were quantified by specialized food processing software and collected on an hourly basis over a three-day period using a validated ad libitum vending machine paradigm. Body composition was assessed by DXA. Lagged multi-level models accounting for age, sex, race/ethnicity, fat and fat free mass indices were fitted to examine the impact of prior macronutrient content on subsequent meals. RESULTS: Protein intake was associated with decreased energy intake (Kcal; B = -1.67 kcal, p = 0.0048), lower protein and carbohydrate intake (B = -0.08 g, p = 0.0006; B = -0.21 g, p = 0.0003, respectively) at subsequent meals. Daily Macronutrient intake and subsequent intake were positively associated. CONCLUSIONS: Dietary protein exhibits a negative regulatory effect on a short-term meal-to-meal rather than day-to-day basis. In the setting of readily available food, protein intake impacts energy intake only over very short time courses.

Time-series analysis of presentations to four syringe dispensing machines and a needle and syringe programme during COVID-19 lockdowns in Melbourne, Australia.

BACKGROUND: Australian harm reduction services are provided via a mix of modalities, including fixed-site needle and syringe programmes (NSP) and syringe-dispensing machines (SDMs). SDMs are cost-effective and provide 24-h anonymous access to needles/syringes, often to underserved geographic areas, and can attract clientele who may choose not to use NSPs. The introduction of COVID-19 control measures saw disruptions and adaptations to the provision of harm reduction services. It is possible that SDMs filled the gap in otherwise disrupted harm reduction services in Melbourne. In this paper, we use data from four SDMs and an NSP to explore changes to harm reduction usage during periods of COVID-19 lockdowns in Melbourne, Australia, in 2020. METHODS: Our data span September 2017-December 2020. We analysed daily counts of SDM use and monthly counts of NSP use, according to unique presentations to both. Auto-regressive integrated moving average (ARIMA) time-series models were fitted to the data with the effects of lockdowns estimated via a step function. RESULTS: Across the study period, we estimated 85,851 SDM presentations and 29,051 NSP presentations. Usage across both the SDMs and the NSP declined during the COVID-19 lockdowns, but only the decline in SDM usage was significant in ARIMA analysis. CONCLUSIONS: The slight, but significant decline in SDM use suggests barriers to access, though this may have been mitigated by SDM users acquiring needles/syringes from other sources. The decline, however, may be a concern if it led to lowered needle/syringe coverage and a subsequent increase in injecting risk. Further work is needed to properly explore potential changes in preference for needle/syringe acquisition site and associated barriers. Importantly, this work adds to the body of literature around the impacts of COVID-19 on harm reduction provision and potential areas of improvement.

Analysis of four syringe dispensing machine point-of-access data 2017-2020 in Melbourne, Australia: machine utilisation and client demographics.

BACKGROUND: Australian needle and syringe distribution occurs via a mix of modalities, including syringe dispensing machines (SDMs). SDMs are electronic vending machines providing (often) 24-h access to needles/syringes and may attract greater numbers of people who are younger, female, and/or have limited connection to health care services compared to individuals accessing fixed-site needle and syringe programs (NSPs). However, validating the demographic characteristics of SDM clients has proven difficult in previous research. METHODS: In this paper, we analyse SDM order and client demographic data from four SDMs located in South-East Melbourne, Australia, and compare this against the managing fixed-site NSP between May 2017 and December 2020. SDM data were collected via a novel 0-9 numeric keypad input tool. Via the tool, SDM clients were requested to input their categorised age, gender and postcode. Given the novelty of the tool, we evaluate the feasibility of the data collection method. We analysed data according to: (1) total SDM orders made, (2) estimated 'unique SDM presentations' and (3) describing the demographics of unique SDM clients. Importantly, we noted substantial invalid demographic data, and consequently, severely restricted data for analysis. RESULTS: There were 180,989 SDM orders made across the four SDMs to an estimated 90,488 unique SDM presentations. There was little variation in unique presentations across days of the week, but 69% occurred out of NSP operating hours. Across the study period, the SDMs distributed 66% of the number of syringes distributed by the fixed-site NSP. Due to invalid demographic data, our restriction method provided only 10,914 (6% of all data) unique presentations for analysis. There were some demographic differences between SDM and NSP client, but these should be treated with caution. CONCLUSIONS: The data collection tool provides a novel means of comparing SDM and fixed-site presentations, demonstrating the substantial expansion of service via the SDMs. However, the validity of the demographic data was highly questionable and requires significant data coding, meaning it is not feasible for community NSPs. While we recommend the inclusion of automatically collected SDM order data, the use of a 0-9 numeric keypad to collect demographic data-while an innovation-requires alteration to support NSP data.

Anonymous Linkage Between College Students and Human Immunodeficiency Virus (HIV) Facilities: Systematic Evaluation of Urine Self-Collection for HIV Testing Initiative in China.

BACKGROUND: Identifying young individuals living with human immunodeficiency virus (HIV) who are unaware of their status is a major challenge for HIV control in China. To address this, an innovative, anonymous vending machine-based urine self-collection for HIV testing (USCT) program was implemented in 2016 in colleges across China. METHODS: From June 2016 to December 2019, 146 vending machines stocked with urine self-collection kits were distributed on 73 college campuses across 11 provinces of China. Urine samples were collected, delivered, and tested in an anonymous manner. We analyzed the returned rate, reactive rate (likelihood of HIV screening positive), testing effectiveness (the annual number of college students living with HIV screened by USCT or other testing methods), and the spatiotemporal relationship between USCT usage and student activity per college generated from the usage of a social networking application. RESULTS: Among the 5178 kits sold, 3109 (60%) samples were returned; of these, 2933 (94%) were eligible for testing. The HIV reactive rate was 2.3% (66 of 2933). The average effectiveness ratio among the 34 participating Beijing colleges was 0.39 (12:31) between USCT and conventional testing methods. A strong spatiotemporal correlation between USCT numbers and online student activity was observed during school semesters in Beijing. CONCLUSIONS: USCT is a powerful complement to current interventions that target at-risk students and promote HIV testing. The social networking-based evaluation framework can be a guide in prioritizing at-risk target populations.

Supporting visitor compliance with a smoke-free policy at hospital using a nicotine replacement therapy vending machine.

ISSUE ADDRESSED: To support visitors to comply with Central Coast Local Health District's (CCLHD) smoke-free hospital grounds policy, a need was identified for round-the-clock availability of nicotine replacement therapy (NRT). Providing NRT through a vending machine was identified as a possible solution. This initiative complemented other strategies that provide staff and patients who smoke with NRT. METHODS: NRT was originally provided through a snack vending machine; however, there were commercial and regulatory concerns with this method. In 2015, dedicated NRT vending machines were installed at Gosford and Wyong Hospitals, and were operated by the Health Promotion Service. The appropriate regulatory permission was gained to supply a specific brand of NRT. Sales and incident data were recorded, and ongoing smoking counts were performed both before and after installation. RESULTS: In all, 247 sales of NRT gum were made through the vending machines from early 2017 to late 2019. Smoking counts show that there are very low rates of visitor smoking (<1%) in the approximately 4.5 years pre- and post-installation of dedicated vending machines. There was no statistically significant change in the smoking rate of visitors since the vending machine was installed at Wyong Hospital. CONCLUSIONS: While NRT is generally provided to patients and staff within health settings to support compliance with smoke-free policies, alternatives to smoking for visitors are typically overlooked. A NRT vending machine achieves this. However, because there are few purchases made, the vending machines as currently operating are unlikely to make any significant impact on smoke-free policy compliance at these hospitals. SO WHAT?: While vending machines have limited effectiveness on overall smoke-free policy compliance, this strategy may have applicability to all sectors with smoke-free policies, especially those operating 24 hours a day, as a means of providing an alternative to smoking for visitors.

Toward street vending in post COVID-19 China: Social networking services information overload and switching intention.

With the progress of epidemic containment, the Chinese government has relaxed its regulatory policies on street vending, hoping to help people who have lost their livelihoods and to assist in the restoration of social and economic order. In response, Chinese people poured into the stall economy, especially individual peddlers, with great expectations for street vending. Street vending has become a hot topic on Chinese social network sites (SNSs). Based on the push-pull-mooring framework, SNS information overload theory was introduced and combined with the actual situations of street vending in China, and a structural equation model was established to study factors affecting individual Chinese peddlers' intention to engage in street vending and the effects of SNS information overload on these factors. Results revealed that perceived policy benefits, subjective norms, and switching cost perceptions of individual peddlers were positive factors affecting their intention to engage in street vending. SNS information overload positively affected individual peddlers' dissatisfaction with their original business model, anxieties over their livings, perception of policy benefits, and subjective norms but negatively affected individual peddlers' perception of switching costs.

Application of nutrient profile models to compare products offered in 'healthy' vs 'conventional' vending machines in a Spanish hospital environment.

INTRODUCTION: Vending machines promote easy access to food with low nutritional value. 'Healthy' vending machines (HVM) have been introduced as a means to improve the availability and accessibility of healthy food options, and the healthiness of the foods, however, has not been evaluated. OBJECTIVE: Our aim was to assess the healthiness of the products offered in HVM and 'conventional' vending machines (CVM), located in the Catalan Institute of Oncology. STUDY DESIGN AND METHODS: All products available in vending machines (HVM (n = 33) and CVM (n = 62) were evaluate during three nutrient profile models (NPMs): the World Health Organization's European Regional Office model (WHO), Nutrient Profile Model UK (NPM-UK), and Australian Health Star Rating system (HSR). RESULTS: Regardless of the NPM used, significant differences found in the proportion of healthy products among HVM and CVM (WHO: P-value = 0.005, NPM-UK: P value < 0.001, HSR: P-value < 0.001). The healthy products offered in HVM accounted for 30%, 73%, and 52% of the total content, while CVM offered 6%, 32%, and 15% of the content, as assessed by WHO, NPM-UK, and HSR, respectively. The WHO model was the most restrictive model, and the NPM-UK was the most permissible one. CONCLUSIONS: Although not all products in HVM are rated as healthy by the different NPMs, the percentage of healthy products was significantly higher than those in CVM.

Condom-vending machines in Italy: a qualitative exploration of gender differences to improve promotion and use.

OBJECTIVES: The purposes of this study were to explore gender differences in condom purchasing from condom-vending machines (CVMs) and identify ways to improve CVM promotion. METHODS: Semi-structured interviews with 42 men and women aged 18-50 years (mean ± standard deviation, 29.1 ± 7.9) and living in or near Florence, Italy, were conducted between May and June 2019. Techniques from expanded grounded theory-guided data analysis allowed for a constant comparative approach to contextualise data and identify emergent themes. RESULTS: Three themes emerged: (1) attitudes and barriers towards CVMs; (2) gender-specific purchasing influences and behaviours; and (3) CVM improvement and promotion. Women and men described varied concerns surrounding CVM purchasing, illuminating reasons for hesitancy. Focussing on CVM quality and improving product offerings were suggested by participants to increase use. CONCLUSION: Findings offer practical recommendations to guide CVM messaging to increase access to and use of condoms and other personal care items. Men were cited as primary CVM users, expressing practical concerns surrounding CVMs, while, for women, CVM visibility was as much an advantage as a drawback. Reflecting consumer needs via diversified product offerings should be considered a priority for increased CVM use. Working to promote CVMs requires clear messaging that attends to gender norm limitations, details product safety and establishes CVMs as a reliable condom purchase outlet.

Altering the availability of healthier vs. less healthy items in UK hospital vending machines: a multiple treatment reversal design.

BACKGROUND: Altering the availability of healthier or less-healthy products may increase healthier purchases, but evidence is currently limited. The current study aimed to investigate the impact of altering the absolute-and-relative availability of healthier and less-healthy products - i.e. simultaneously altering the number of options available and the proportion of healthier options - in hospital vending machines. METHODS: An adapted multiple treatment reversal design was used, altering products available in ten vending machines serving snack foods and/or cold drinks in one English hospital. Machines were randomised to one of two sequences for the seven 4-week study periods: ABCADEA or ADEABCA. In Condition A (study periods 1, 4 and 7) the proportions of healthier products were standardised across all machines, so that 25% of all snack slots and 75% of drink slots were healthier. In Condition B, 20% of vending machine slots were emptied by removing less-healthy products. In Condition C, the empty slots created in Condition B were filled with healthier products. Conditions D and E were operationalised in the same way as B and C, except healthier products were removed in D, and then less-healthy products added in E. Sales data were obtained from machine restocking records. Separate linear mixed models were conducted to examine the impact of altering availability on energy purchased (kcal) from (i) snacks or (ii) drinks each week, with random effects for vending machine. RESULTS: The energy purchased from drinks was reduced when the number of slots containing less-healthy drinks was decreased, compared to standardised levels (- 52.6%; 95%CI: - 69.3,-26.9). Findings were inconclusive for energy purchased from snacks when less-healthy snack slots were reduced (- 17.2%; 95%CI: - 47.4,30.5). Results for altering the number of slots for healthier drinks or snacks were similarly inconclusive, with no statistically significant impact on energy purchased. CONCLUSIONS: Reducing the availability of less-healthy drinks could reduce the energy purchased from drinks in vending machines. Further studies are needed to establish whether any effects might be smaller for snacks, or found with higher baseline proportions of healthier options.