Hospital Food Service Strategies to Improve Food Intakes among Inpatients: A Systematic Review

This review aims to identify hospital food service strategies to improve food consumption among hospitalized patients. A systematic search that met the inclusion and exclusion criteria was manually conducted through Web of Science and Scopus by an author, and the ambiguities were clarified by two senior authors. The quality assessment was separately conducted by two authors, and the ambiguities were clarified with all the involved authors. Qualitative synthesis was used to analyze and summarized the findings. A total of 2432 articles were identified by searching the databases, and 36 studies were included. The majority of the studies applied menu modifications and meal composition interventions (n = 12, 33.3%), or included the implementation of the new food service system (n = 8, 22.2%), protected mealtimes, mealtime assistance and environmental intervention (n = 7, 19.4%), and attractive meal presentation (n = 3, 8.3%). Previous studies that used multidisciplinary approaches reported a significant improvement in food intake, nutritional status, patient satisfaction and quality of life (n = 6, 16.7%). In conclusion, it is suggested that healthcare institutions consider applying one or more of the listed intervention strategies to enhance their foodservice operation in the future.


Introduction
Reduced food intake among hospitalized patients or inpatients is often associated with adverse health consequences such as malnutrition. Malnutrition is described as a lack or excess of nutrients, imbalance in macro-and micronutrient intakes, or both, resulting in irregular body structure, function, and clinical outcomes [1]. Malnutrition during hospitalization is a crucial problem; approximately 32% of patients are malnourished, and 23% eat less than 25% of the provided hospital food [2].
Malnutrition has several negative consequences, including a weakened immune system and slower wound healing, muscle wasting, longer hospital stays, increased treatment cost and a higher mortality rate [3]. A study showed that a lack of physical activity and/or a lower protein intake in patients due to the lower energy intake might result in muscle atrophy during a few days of hospitalization [4]. A low body mass index (BMI) at admission, concurrent illnesses and infections, a lack of food intake and quality, and male sex were significant factors influencing food intake and causing malnutrition among inpatients [5].
There are many factors associated with inadequate food intake among inpatients, such as lack of feeding aid, inability to provide daily healthy meals, and missing meals due to clinical investigations [1]. A previous statistic showed that about 58% of inpatients did not consume all the foods they were served [6]. According to the findings, factors related to food intake during hospitalization are related to both patients' condition and the quality of the hospital food. Factors related to patients' condition include physical characteristics, such as difficulties eating and swallowing. Psychosocial factors include being alone, neglected, stress and food beliefs, while examples of hospital food quality factors are unhygienic food and delayed mealtimes. These factors were reported to be significantly associated with increased food waste [7]. Moreover, nutritional impact symptoms include abdominal distention, dysphagia, diarrhoea, nausea, vomiting, lethargy, low appetite, being too sick or too tired to eat and poor dentition. The other conditions, such as interruptions during mealtime, not having food when a meal is missed and refusing to eat the ordered food were highly associated with inadequate food intake during hospitalization [8].
Identifying and managing malnutrition is essential because inappropriate nutritional support for inpatients with malnutrition leads to a higher transfer and mortality rate, longer hospital stay, and a lower discharge rate than well-nourished patients. It is suggested that future research should concentrate on the factors that contribute to insufficient food intake and the development of effective methods for reducing the risk of malnutrition in inpatients [9]. Additionally. the organization of food provision in hospital could harm patients' food intake and nutritional status due to patients' dissatisfaction with hospital meals, missed diagnoses due to inaccurate nutritional screenings and assessments, and the lack of training and hospital staff awareness [8][9][10]. Hence, it is essential to include a nutritional assessment as part of the patient's clinical diagnoses. In addition, hospitals should develop systematic methods to prevent and treat malnutrition. These involve an interdisciplinary care team, such as a physician, dietitian, nurse, and pharmacist, working to develop a nutrition care plan, establish effective processes to diagnose malnourished patients and introduce comprehensive nutrition care plans [11].
Therefore, this systematic review aims to identify and integrate studies on hospital food service strategies to improve food intake among inpatients. This review considered the food service system, nutrition care plan, physical and environmental impact, and outcome strategies that help increase cost-effectiveness, optimize productivity, promote patients' food intake, and improve nutritional care.

Materials and Methods
The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used for the identification and evaluation of eligibility for the articles included in this systematic review [12] (Supplementary File S1). The systematic review was registered with the International Prospective Register for Systematic Reviews (PROSPERO) (CRD42021272357).

Search Strategy
Journals were searched using electronic databases from Web of Science and Scopus. At the first stage, the search strategy was a complete search string/query string and/or keywords, such as: "hospital foodservice", "hospital", "food service", "catering", "food quality", "meal quality", "patient satisfaction", "food intake", and "meal intake". Boolean operators such as "AND" and "OR" were used where appropriate to combine the searches. Inclusion criteria such as publication years (2010 until 2019), document type (articles and conference), publication stage (final), source type (journals and conference proceedings), and language (English) were applied as search strategies during this stage. At the second stage, duplicate articles were identified, and the titles and abstracts were checked if they were relevant to the topic. Later, the filtered articles were further screened by reading individual manuscripts. Manuscripts that did not meet the requirements for inclusion were not considered.

Eligibility Criteria
After the screening process, the eligibility process was conducted according to the inclusion and exclusion criteria, which were selected based on the aims and objectives of the review paper. The study must be set up at the hospital food service area and conducted in any unit/ward in a hospital. The studies on relevant topics that were not conducted under the hospital food service process or dietetics department were excluded from the review process. The subjects involved in the study must be hospitalized patients who are 18 years old, and above, food service staff and/or other medical/healthcare professional staff such as nurses, doctors, medical assistance, and patients' caregivers; these were also included as inclusion criteria. Published quantitative data papers in journals and conference proceedings were included in this study. The following parameters were set as inclusion criteria: patient food intake, nutritional status, patient satisfaction, plate waste, and quality of life. Studies on relevant topics that were not conducted under the hospital food service or dietetics department were excluded from the review process. Only complete manuscripts for journals and conference proceedings were included in this study.

Data Extraction and Management
Data extraction was carried out using a template created and verified specifically for this review. The data extracted from each study were the citation, aim or objectives, study population (study design, sample size, age group, and study duration), methodology (control and intervention groups), outcome parameters and findings. The first author manually performed the extraction (N.S.O.). The data extraction was then reviewed, and ambiguities were verbally clarified with the second and third senior authors (N.M.N. and M.S.M.S.). At the same time, quality assessment of the reviewed articles was separately conducted by the fourth and fifth authors (S.B.A.H. and S.R.). Later, the quality assessment was reviewed, and ambiguities were verbally clarified with all the authors involved in this review. The findings were summarized using qualitative synthesis by the first and forth authors, with the fifth author involved where necessary. The summarized results are categorized following the intervention strategies for hospitalized food services and improvements in food intake, nutritional status, or patient or overall hospital food service operation satisfaction.

Quality Assessment
The Quality Criteria Checklist for Primary Research (QCCPR) was used to determine each study's quality, including criteria for assessing the study's validity and bias [13]. The tool consists of four relevant questions that address applicability to practice. The research issue, sample population, sampling (bias and randomization), intervention or exposure, measurement results, statistical analysis, and interpretation of findings were among the ten validity questions [14]. The studies' quality was rated as positive, neutral, or negative. A positive rating indicates that most aspects of the study met the validity criteria. In contrast, a neutral rating suggests that the study is not remarkably strong, according to the Academy of Nutrition and Dietetics' QCCPR. A negative rating indicates that most of the study fails to meet the validity criteria.

Data Analysis and Synthesis
Meta-analysis was not possible due to the high heterogeneity across the studies included in this review. The authors decided to compare and summarize any statistical significance in the studies included in this review. The independent variables (the type of intervention study, such as food service system, menu modification, environment, and physical intervention) and dependent variables (food intake, food records, visual estimation tools, BMI, weight changes, patient satisfaction, quality of life, etc.) were evaluated by the first and fourth authors during the analysis, and all the findings were then compared and summarized in Table 1.  Patient meal experience survey = significant increase in BMOS receiving ordered food (p < 0.001), able to choose their preferred food (p = 0.006) and able to assess nutritional information of the menu (p = 0.002) compared to the PM. A significant increase in food intakes and meal experience improved upon access to nutritional information in the intervention group. Increased intake of food, energy, protein, and sodium in IG by 8% (p < 0.05), 10% (p < 0.01), 9% (p < 0.01), and 53% (p < 0.01), in all patients, and by 13% (p < 0.01), 19% (p < 0.01), 17% (p < 0.01), and 67% (p < 0.01).
Increased intake of food, energy, protein, and sodium intake in lunch with condiments.
Significant increases in energy and protein intake, improved patient satisfaction, reduced plate waste and food cost in the intervention group. The number of patients with sufficient food consumption was doubled, and mean energy and protein intakes were significantly higher. The mean of energy and protein intake, weight, and overall patient satisfaction in the intervention group was significantly increased.  Protein intake higher in the intervention group except for dinner. Higher energy and protein intakes and mealtime preferences among patients in the dining room. Most of the patients preferred the BMOS and mean daily energy and protein intakes were significantly increased in the intervention group. Nutritional status: 74% patients achieved their goal weight at the end of the intervention period. Food intake: nonsignificant decrease in total grams of main-plate food consumed during the six-month intervention period when compared with the control period (p = 0.11).
Most of the patients in the intervention group achieved their weight goals. No significant difference in main-plate food intake. Higher fat intake in the intervention group.

Foodservice System Intervention
Eight studies (n = 8, 22.2%) implemented a new food service system in their hospital to improve patients' food intake, focused on the meal-ordering system, service styles, and meal delivery [23,25,26,30,32,34,37,43]. Most of the studies reported positive improvements in patients' food intake and satisfaction. They had a better meal quality, meal experience, oral nutritional support and reduced food waste and cost [23,25,26,30,32,37,43]. In contrast, one study showed no difference between bistro style and pre-plated services in terms of (i) energy or protein consumption, (ii) inpatient satisfaction, and (iii) meal quality [34].

Menu Modification and Meal Composition Intervention
Menu modification and meal composition interventions were used in several studies (n = 12, 33.3%) to enhance patients' food consumption, nutritional status, quality of life, and food production costs. Most of the studies reported improvements in total energy and protein, nutritional status, patients' satisfaction, quality of life, as well as reductions in labour and food production cost [15,22,24,33,35,41,44]. Two studies reported no significant difference in total energy intake in both groups [16,20]. One study reported no significant difference in food intake over time; however, fat intake was increased during the intervention period [47]. Another study identified a positive relationship between meal portion size and plate waste, and reported increased food waste in patients at nutritional risk during supper [35].

Multidisciplinary Approaches Intervention
Six studies (n = 6, 16.7%) adopted multidisciplinary approaches as their primary intervention strategy to improve patients' food intake. The studies recorded interdisciplinary approaches at the individual-, ward-, and organizational level, or a combination of these. All studies reported an increase in food and nutrient intake, with a high percentage of patients meeting energy requirements, and showing improved body weight, increased patient satisfaction and increased quality of life [16,19,21,28,31,48].

Protected Mealtime, Mealtime Assistance, and Environment Intervention
Seven studies (n = 7, 19.4%) applied protected mealtimes, mealtime assistance, and environmental interventions as their intervention approach to improve patient food intake [10,18,27,38,40,42,46]. A study was performed to establish the patient-related variables and aspects of protected mealtimes that correlated with adult inpatients' energy and protein intakes [10]. Two studies (n = 2) that used a protected mealtime program showed an improvement in protein and energy intake among inpatients [10,38]. In contrast, one study reported no energy and protein intake changes in control and intervention groups, as well as a deficit in energy intake in the intervention group [18]. Two studies (n = 2) reported that mealtime assistance in the form of between-meal snacks served by the food caregiver led to an improvement in energy and protein intake, as it encouraged and motivated patients to eat [42,46]. One study implemented a mealtime environment indicative of patients' preferences to have their meals in the dining room, based on the improvements seen in their energy and protein intake [40]. In contrast, another study reported a decrease in protein intake after the intervention, even though the mealtime environment was improved [27].

Meal Presentation Intervention
Of the 36 included studies, only three studies (n = 3, 8.3%) used meal presentation as their intervention strategy to improve the patients' food intake [17,36,45]. All the studies reported improved food intake and satisfaction, as well as reductions in the intervention group's food cost and readmission rate. The differences in protein intake per mealtime between the traditional three-meals-a-day food service (TMS) and a novel six-times-a-day food service, FoodforCare (FfC), which included protein-rich food products, was compared in a study that reported that the intervention group had a higher protein intake at all mealtimes except dinner [36]. However, the highest protein intake was recorded at dinner by both food services. Another study reported that loss-of-appetite patients who received meals with an improved display had a significantly higher food intake as compared to those who received a standard meal [45]. Patients in the orange napkin group consumed more hospital-provided food than those in the white napkin group [17]. The intervention group's patients were also slightly more satisfied with the hospital's food service.

Food Intake
Food records, food weight, and visual estimation methods were identified as tools to determine the inpatient food intake in all studies included in this review. Nine out of 36 studies (25%) applied food records and showed a positive outcome in their studies [15,[21][22][23][24]26,28,44,48]. Four of the nine studies (n = 4) used validated hospital foodservice management systems developed by the respective hospitals to determine the food intake of the patients [15,22,26,44]. Two studies used the traditional food intake record method, which involved a 24-h dietary recall interview and food record in nursing flow sheets, as the standard food intake monitoring method [21,48]. Nine studies (25%) used a scale to weigh meals prior to and after mealtime [19,27,29,32,36,37,41,42,46]. Additionally, 14 studies (38.8%) used visual estimation to record the portion size of the meal that was consumed [10,17,18,20,25,30,31,34,35,39,43,45,47,49]. Eleven studies recorded the portions of consumed food in exact percentages, while three studies used validated photographic software programs. Only two studies (6%) reported using both food record and visual estimation methods to verify patients' dietary records in their studies [16,33].

Patient Satisfaction
Patient satisfaction was assessed in ten of the 36 studies (27.8%), with most studies using validated questionnaires [17,24,26,28,30,[33][34][35]41,43]. Two of them used the Acute Hospital Foodservice Patient Satisfaction Questionnaire (AHFPSQ), which was adapted from a previous study by Capra et al. [50]. The scores were given according to four domains: meal service, food quality, physical environment, staffing and service. The remaining studies used the validated patient satisfaction survey developed by their respective hospitals [17,24,38,40,44]. One study used the Nutrition Related Quality of Life Questionnaire to score six clusters on a scale from 1 to 6 (general health, food resource, food quality, service, and autonomy) [26]. One study used The Meal Assessment Tool to measure meal flavour, taste, appearance, and quality. In contrast, the Meal Quality Audit Tool was used to assess the sensory properties and temperature of the meal by the dietitian observers [34]. Only one study (10%) used a semi-structured interview guide to evaluate satisfaction, hosting intervention, and dining setting [28].

Discussion
Many factors are associated with malnutrition among inpatients. One of them is a decline in food consumption because of an illness-induced loss of appetite. A study in 56 countries showed that inpatients had inadequate food intake, which was significantly associated with reduced food intake [51]. Other significant factors are surgical procedures, concurrent illnesses and infection, low BMI upon admission, dissatisfaction with food quality, gastrointestinal symptoms, and inability to chew and swallow [5]. Regardless of age, gender, marital status, employment status, or diagnosis, a high prevalence of malnutrition among inpatients was associated with a longer hospital stay [52,53].
Nutritional intervention and strategies have significantly improved patients' food intake, satisfaction, nutritional status, and quality of life, and reduced food waste and cost [23,25,26,30,33,37,44]. A new food service system was implemented using current technology that focused on the meal-ordering system, service styles, and meal delivery. For example, the use of electronic menus (E-menus) as an alternative approach to the meal-ordering system was an effective way to obtain information about the food, con-tributing to greater satisfaction among inpatients [54]. The bedside meal-ordering system showed improved food intake and patient satisfaction compared to traditional paper menu systems [25,43]. Assistance and guidance during meal orders can increase the suitability and consistency of orders, and monitor the nutritional status of patients. The meal-ordering system also helps determine patients that are at risk of malnutrition. It indirectly improves clinical outcomes where dietary education is needed [55]. Regardless of the use of new technology in the meal-ordering system, simple interventions such as verbal prompts for meal-ordering have proven to be a helpful tool to improve food consumption among patients during hospitalization [23].
Room service is now trending in many hospital food service operations. Room service increases patient satisfaction and food intake, while reducing food waste and cost [26,30]. Meal delivery systems play an essential role in monitoring and assessing patients' food intake. Inpatients preferred the trolley system over the pre-plated meal system because the temperature was more controlled [56][57][58]. However, one study compared Bistro-style meals and pre-plated services and reported no significant differences in the patients' food intake, satisfaction, and meal quality [34]. In a previous study comparing the same meal distribution system between prison and hospital food service, the delivery and service system were much less consistent (delay and disruption) in hospitals than in prison due to poor communication and the demands of medical professionals [59].
It is crucial to ensure patients' total energy and protein intake meets the recommended requirements of the British Dietetic Association's (BDA) and Nutrition and Hydration Digest Standard [60]. Most of the studies implemented menu modifications and composition interventions, such as energy-and protein-enriched meals or snacks, added condiments to the menu, and provided oral nutritional supplements with a combination of high-protein and high-energy snacks to the patient when promoting food intake [15,22,24,29,35,44]. It is suggested that total energy and protein requirements can be met by offering more energydense menu choices and optimizing the provision of hospital, snack, and oral nutritional supplements, as clinically recommended [61]. The patient-centered foodservice model is suggested to result in increased food intakes and improved nutritional status, as well as increases in patient satisfaction and quality of life, and reduced food costs [33]. The patient-centered model definition, in theory, benefits patients by improving communication, providing effective intervention, increasing satisfaction, and obtaining patient-reported outcomes [62].
This review also discovered that multidisciplinary approaches are one of the main intervention strategies to improve patients' food intake. This interdisciplinary approach refers to active teamwork among the various healthcare team members to develop and deliver optimal care plans for inpatients [63]. It is a fundamental strategy to enhance the quality of food intake and patient wellbeing, decrease hospital stays, reduce costs, and support better health outcomes [64]. Multidisciplinary approaches to nutritional supervision are highlighted and indicated, regardless of whether they are individual, ward-based or organizational approaches, or a combination of the three. These have been reported to improve the patients' food intake, nutritional status, satisfaction, and quality of life [16,19,21,28,31,48]. Nutrition interventions to tackle malnutrition are a low-risk, cost-effective approach to improving the quality of patient care; however, they require interdisciplinary collaboration. All healthcare team members (including dietitians, nurses, and physicians) are encouraged to communicate openly across disciplines and recognize the critical role of nutrition care in improving patient outcomes [65].
Protected mealtimes, mealtime environment, and mealtime assistance have been proven to be successful interventions to improve overall patients' food intake. However, the effectiveness of protected mealtimes initiatives in increasing patients' food intake has yet to be proven. Palmer and Huxtable [10] found many aspects of protected mealtimes to be linked to inpatient food intakes, including the introduction of mealtime volunteers and assistance and a proper mealtime atmosphere, which included conditions such as time and position during mealtimes. The same finding was revealed: food intake among elderly patients improved in the presence of meal assistants [66]. Markovski et al. [40] suggested that the dining room environment may positively impact food intake and enjoyment, potentially improving weight gain and nutritional status among elderly patients.
Furthermore, another study demonstrated that mealtime volunteers can improve mealtime treatment for adult patients or residents in institutional settings [67]. However, little well-designed research is available on mealtime volunteers or feeding assistance. By removing obstacles and creating an environment of support and personal attention during hospital mealtimes, feeding assistance is an essential technique for increasing elderly patients' food intake [46]. Although the patients may experience various side effects and discomforts resulting from their illness, they still improved their food intake. Lindman et al. [42] also proposed that educated and trained food caregivers or assistants played a vital role in multi-professional nutritional management.
In contrast, Hickson et al. [27] reported that the protected mealtimes program in inpatients did not improve nutritional intakes, noting the energy deficit as a non-significant improvement. Another study by Porter et al. [18] also showed a limited improvement in food intake after implementation of the Protected Mealtime program. System-level nutrition intervention could increase food intake among patients at risk of malnutrition through fortified meals, mid-meals and mealtime assistance [38]. Previous studies reported that protein-supplemented hospital food substantially affected total protein intake and weight-adjusted energy intake among nutritionally vulnerable patients [68].
Furthermore, the meal presentation for cancer patients was also associated with higher plate wastage [69]. Food garnishes and attractive presentation encourage patients to try the food despite low appetites after treatment. Previous studies showed that patient satisfaction with hospital meals appeared to be strongly influenced by food variety, taste, presentation, flavour, and preparation [70][71][72][73]. Thus, a broader menu, high-quality taste, specific ingredient details, and improved mealtime, delivery, and food presentation will improve patient satisfaction with hospital foodservices [71,72]. Navarro et al. [45] found that enhanced meal presentation increases food consumption and patient satisfaction and decreases food costs and readmission rates. Research conducted by the same researchers, Navarro et al. [17], to compare the use of orange (experimental) and white (control) napkins on the inpatients' meal intake showed improved patient satisfaction with hospital food service and increased food intake among patients with an orange napkin.
Moreover, implementing high-frequency food services containing protein-rich meals and attractive meal presentation led to improved protein intake at mealtimes during the day [31]. A recent study was conducted by Donnelly et al. [74] to compare the efficacy of blue versus white dishware in increasing food consumption and mitigating eating challenges among dementia residents. This systematic review concluded that the factors affecting food intake among residents living with dementia were complex. A simple intervention was insufficient to improve their dietary intake.

Limitations of Study
The key strength of this systematic analysis is the use of strict inclusion criteria, which ensures that appropriate intervention methods are chosen for hospital food services to increase patients' food intake and nutritional status. Studies that were not conducted in healthcare settings were omitted because they did not measure the primary outcome and did not include inpatients. When evaluating the results of this systematic review, some limitations should be considered. This study used Clarivate Analytics' Web of Science and Scopus databases as keyword-searching engines. Most of these databases, such as PubMed, Google Scholar, and Cochrane Library, were practical and offered various search facilities. However, Scopus covers a more comprehensive journal range and has a greater citation analysis capability than Web of Science. By comparison, the Web of Science features more attractive graphics and a more comprehensive overview of citations than the Scopus database [75]. Another constraint of this systematic analysis is that clinical heterogeneity was not considered. Heterogeneity is defined in a systematic review as any variation between studies, while clinical heterogeneity is defined as variation among the participants, treatments, and outcomes studied [76]. Although assessing clinical heterogeneity is relevant and should be considered in this systematic review, the authors have limited access to guidance in the processes of selecting potential effects and measuring modifiers. Additionally, variability is not always precisely quantified due to the imprecise definitions of intervention procedures, populations, and outcomes [77].

Conclusions
This review looks at evidence-based intervention strategies for hospital food service operators to improve patients' food intake, satisfaction, nutritional status, and quality of life. Five intervention strategies were identified: implementing a new food service system, menu modification, multidisciplinary approaches in nutrition care, protected mealtime intervention programs, and attractive meal presentation. Although the meal presentation intervention strategy is less used in current hospital food service practice, it was evidenced to improve patients' dietary intake and satisfaction, as well as reduce food cost and readmission rates. Thus, this review suggests that healthcare institutions should consider applying one or more of these interventions to improve their food service operations in the future.