Social facilitation of food intake is mediated by meal duration

Meal Duration and Obesity-Related Indicators among Adolescents: Insights from the EHDLA Study

PURPOSE

This paper aims to examine the association between meal duration and obesity indicators among Spanish adolescents.

METHODS

We conducted a cross-sectional analysis using data from the Eating Healthy and Daily Life Activities (EHDLA) project involving 755 adolescents aged 12 to 17 years (54.8% girls) from three secondary schools in the Valle de Ricote Region of Murcia, Spain. To evaluate overall meal duration, participants were asked how long (on average) breakfast, morning snacks, lunch, afternoon snacks, and dinner typically last. Subsequently, global meal duration was measured, and the participants were categorized into tertiles. Obesity-related indicators, including body mass index (BMI) z score, waist circumference (WC), and skinfold thickness, were assessed. The analyses were adjusted for potential confounders such as sex, age, socioeconomic status, physical activity, sedentary behavior, diet quality, and energy intake.

RESULTS

Concerning meal duration status, adolescents with long meal durations had the lowest estimated marginal means of BMI z score, WC, and body fat percentage (using the sum of triceps and calf skinfolds). However, significant differences between adolescents with a long meal duration and those with a short meal duration were observed only for BMI z score (p = 0.008), and WC (p = 0.020). Furthermore, significant differences in BMI z score (p = 0.017) between adolescents with a long meal duration and those with a moderate meal duration were identified.

CONCLUSIONS

These findings underscore the importance of promoting slower eating habits as part of obesity prevention strategies. Future studies should explore the causality of this association and its potential for behavioral interventions.

The social facilitation of eating: why does the mere presence of others cause an increase in energy intake?

There is strong evidence that people eat more when eating with friends and family, relative to when eating alone. This is known as the 'social facilitation of eating'. In this review, we discuss several gaps in the current scientific understanding of this phenomenon, and in doing so, highlight important areas for future research. In particular, we discuss the need for research to establish the longer-term consequences of social eating on energy balance and weight gain, and to examine whether people are aware of social facilitation effects on their own food intake. We also suggest that future research should aim to establish individual and contextual factors that moderate the social facilitation of eating (e.g. sex/gender), and it should clarify how eating socially causes people to eat more. Finally, we propose a novel evolutionary framework in which we suggest that the social facilitation of eating reflects a behavioural strategy that optimises the evolutionary fitness of individuals who share a common food resource.

Negative energy balance during military training: The role of contextual limitations

During multiday training exercises, soldiers almost systematically face a moderate-to-large energy deficit, affecting their body mass and composition and potentially their physical and cognitive performance. Such energy deficits are explained by their inability to increase their energy intake during these highly demanding periods. With the exception of certain scenarios in which rations are voluntarily undersized to maximize the constraints, the energy content of the rations are often sufficient to maintain a neutral energy balance, suggesting that other limitations are responsible for such voluntary and/or spontaneous underconsumption. In this review, the overall aim was to present an overview of the impact of military training on energy balance, a context that stands out by its summation of specific limitations that interfere with energy intake. We first explore the impact of military training on the various components of energy balance (intake and expenditure) and body mass loss. Then, the role of the dimensioning of the rations (total energy content above or below energy expenditure) on energy deficits are addressed. Finally, the potential limitations inherent to military training (training characteristics, food characteristics, timing and context of eating, and the soldiers' attitude) are discussed to identify potential strategies to spontaneously increase energy intake and thus limit the energy deficit.

A new measurement tool to assess the deliberate overfeeding of others: The Feeder questionnaire

Whilst overeating is often influenced by others in an implicit way, people may also explicitly encourage others to overeat. This has been labelled being "a Feeder" but to date, this more deliberate trait remains neglected. This study aimed to conceptualize being "a Feeder" in terms of motivations and behaviour and to operationalize this construct with a new measurement tool through five stages with three discrete samples. Using the definition of a Feeder as "someone who offers others food even when they are not hungry" a preliminary qualitative study (n = 5) clarified the behaviour of a Feeder and revealed six motivations for such feeder behaviour. These six motivational dimensions and the feeder behaviours were operationalized with individual items and the psychometric properties of the scale were assessed using two independent samples (n = 116; n = 113). The final 27-item measure consisted of six motivational factors (affection; waste avoidance; status; hunger avoidance; offloading; manners) and one behaviour factor, all with good internal consistency (α ≥ .7). The two samples were then merged (n = 229) to describe motivations and behaviour and to assess the association between them. The best predictors of feeder behaviour were love, offloading, manners and status. This new Feeder questionnaire has a strong factor structure and good internal consistency and could be used for further research or clinical practice.

Self-Perceived Eating Habits among Family Caregivers of Older People with Dementia: A Qualitative Study

Research has suggested that family caregivers of older people with dementia often find it difficult to maintain a healthy diet due to the stress of their daily routine, putting them at increased risk of developing lifestyle-related diseases. The present qualitative study aims to clarify the factors that affect the dietary habits of family caregivers of older people with dementia. A total of 21 family caregivers of outpatients with dementia took part in interviews about their diet during a hospital visit in Japan. Qualitative content analysis was used to systematically identify ideas and patterns emerging from the interview data. The data suggest that dementia care helps family caregivers become more conscious of their own dietary lifestyle choices and increases communication opportunities. On the other hand, caregiver burden was found to have a negative influence on the quality and level of interest in dietary choices of caregivers. Providing timely and useful information on care services to family caregivers who might have hesitated to use them in the past was suggested as a useful initiative to relieve caregiver burden. This study clarified five themes related to the eating habits of family caregivers.

Digital Commensality: Eating and Drinking in the Company of Technology

Commensality is a key aspect of social dining. However, previous research has identified a number of pros and cons associated with the incorporation of digital technology into eating and drinking episodes. For instance, those who are distracted by digital technology may eat/drink more (that is, they may overconsume) as a result of their failure to attend to the food-related sensations that are thought to cue the termination of eating. Similarly, it has often been suggested that the use of mobile devices at mealtimes can disrupt the more commensal aspects of dining/drinking (at least among those who are physically present together). At the same time, however, looking to the future, it seems clear that digital technologies also hold the promise of delivering opportunities for enhanced multisensory experiential dining. For instance, they might be used to match the auditory, visual, or audiovisual entertainment to the eating/drinking episode (e.g., think only about watching a Bollywood movie while eating a home-delivery Indian meal, say). Indeed, given the growing societal problems associated with people dining by themselves, there are a number of routes by which digital technologies may increasingly help to connect the solo diner with physically co-located, remote, or even virtual dining partners. In this review of the literature, our focus is specifically on the role of technology in inhibiting/facilitating the more pleasurable social aspects of dining, what one might call "digital commensality." The focus is primarily on Westernized adults with reasonable access to, and familiarity with, digital technologies.

A systematic review and meta-analysis of the social facilitation of eating

BACKGROUND

Research suggests that people tend to eat more when eating with other people, compared with when they eat alone, and this is known as the social facilitation of eating. However, little is known about when and why this phenomenon occurs.

OBJECTIVES

This review aimed to quantify the evidence for social facilitation of eating and identify moderating factors and underlying mechanisms.

METHODS

We systematically reviewed studies that used experimental and nonexperimental approaches to examine food intake/food choice as a function of the number of co-eaters. The following databases were searched during April 2019: PsychInfo, Embase, Medline, and Social Sciences Citation Index. Studies that used naturalistic techniques were narratively synthesized, and meta-analyses were conducted to synthesize results from experimental studies.

RESULTS

We reviewed 42 studies. We found strong evidence that people select and eat more when eating with friends, compared with when they eat alone [Z = 5.32; P < 0.001; standardized mean difference (SMD) = 0.76; 95% CI: 0.48, 1.03]. The meta-analysis revealed no evidence for social facilitation across studies that had examined food intake when participants ate alone or with strangers/acquaintances (Z = 1.32; P = 0.19; SMD = 0.21, 95% CI: -0.10, 0.51). There was some evidence that the social facilitation of eating is moderated by gender, weight status, and food type. However, this evidence was limited by a lack of experimental research examining the moderating effect of these factors on the social facilitation of eating among friends. In 2 studies, there was evidence that the effect of the social context on eating may be partly mediated by longer meal durations and the perceived appropriateness of eating.

CONCLUSIONS

Findings suggest that eating with others increases food intake relative to eating alone, and this is moderated by the familiarity of co-eaters. The review identifies potential mechanisms for the social facilitation of eating and highlights the need for further research to establish mediating factors. Finally, we propose a new theoretical framework in which we suggest that the social facilitation of eating has evolved as an efficient evolutionary adaptation.

Adherence to the French Eating Model is inversely associated with overweight and obesity: results from a large sample of French adults

The ‘French Eating Model’ characterised by structured meals and conviviality has received little attention, although it has been suggested as a potential explanation of the French paradox. This study aims at assessing the adherence to this model in French adults and whether it is associated with weight status. Eating behaviour and, in particular, number of meals per day, snacking frequency, meal time, meal duration, number of courses, position (standing, sitting), presence of others and pleasure experienced was assessed in 2014, in 47 219 participants of the NutriNet-Santé study. A global score of adherence to the French Eating Model was computed on the basis of eating behaviour components. Prevalence of the model was assessed on a sample weighted according to Census data. Associations between adherence to the model (and its components) and overweight and obesity were assessed using logistic regression analyses adjusted for individual characteristics. Most individuals followed the French Eating Model: three meals a day, at set times, sitting at a table with other people and considering meals as a moment of pleasure. Individuals who exhibited higher adherence to the model were less likely to be overweight (OR=0·89; 95 % CI 0·87, 0·92 or obese (0·76; 95 % CI 0·74, 0·79). Similar trends were found for the following components: number of meals per day, snacking frequency, meal time, meal duration and pleasure experience, whereas an opposite trend was observed for the eating with others component. Although prospective studies are needed to conclude on a causal relationship, these results suggested the potential role of the French Eating Model, which is still prevailing in France, in obesity prevention.

To Message or Browse? Exploring the Impact of Phone Use Patterns on Male Adolescents' Consumption of Palatable Snacks

Surveys of mobile phone usage suggest that adolescents habitually use their phones while eating. In this study, we explored whether the manner in which one uses a mobile phone – to engage in a social or non-social activity – can affect appetite regulation. Participants were fifty male adolescents randomly assigned to engage in one of the following phone-based activities: (1) sending and receiving messages (social activity), or (2) reading a neutral article (non-social activity). When given the opportunity to snack, participants in the messaging group consumed more snacks that those who read the article. Our findings correspond to a large literature emphasizing social influences on food intake, and suggest that phone use patterns may predispose an individual to overeating.

Distraction, restrained eating and disinhibition: An experimental study of food intake and the impact of ‘eating on the go’

To assess the impact of distraction on subsequent eating, 60 females consumed a cereal bar while watching TV, walking or talking, and their subsequent desire to eat and food intake were assessed. No effects were found for desire to eat. But while those higher in restrained eating consumed less overall and fewer calories after watching TV or talking, they consumed more overall and more calories (specifically five times more chocolate) if the cereal bar was eaten while walking. ‘Eating on the go’ may disinhibit restrained eaters either as a form of distraction or by offering a justification to overeat.

Improving food intake in persons living with dementia

Persons living with dementia have many health concerns, including poor nutritional states. This narrative review provides an overview of the literature on nutritional status in persons diagnosed with a dementing illness or condition. Poor food intake is a primary mechanism for malnutrition, and there are many reasons why poor food intake occurs, especially in the middle and later stages of the dementing illness. Research suggests a variety of interventions to improve food intake, and thus nutritional status and quality of life, in persons with dementia. For family care partners, education programs have been the focus, while a range of intervention activities have been the focus in residential care, from tableware changes to retraining of self-feeding. It is likely that complex interventions are required to more fully address the issue of poor food intake, and future research needs to focus on diverse components. Specifically, modifying the psychosocial aspects of mealtimes is proposed as a means of improving food intake and quality of life and, to date, is a neglected area of intervention development and research.

Eating in groups: Do multiple social influences affect intake in a fast-food restaurant?

This study investigated multiple social influences to determine whether they affect amount eaten at a fast-food environment. Using observational methods, data on meal duration, foods eaten and personal characteristics were collected for 157 McDonald’s patrons. Analysis of covariance revealed that female diners ate less kilojoules when eating in mixed- versus same-sex groups (adjusted difference = 967 kJ, p < .05), while male diners eating in mixed-sex company ate more in groups compared to pairs (adjusted difference = 1067 kJ, p = .019). Influences to increase and restrict the amount eaten can operate simultaneously in an eating environment with gender a critical factor for consideration.

The social facilitation of eating. A review

The social facilitation of eating (i.e., people eating more in groups than when alone) has been studied for about three decades now. In this paper, we review the empirical research (diary studies, observational studies, and experimental studies) of social facilitation, attending to factors that increase or decrease socially facilitated eating. We also review the various explanations (e.g., "time extension") that have been offered for the effect and offer our own speculations as to the underlying mechanisms. Further, we discuss promising directions for future research on the social facilitation of eating.

Geriatric rehabilitation patients' perceptions of unit dining locations

Background

Eating together is promoted among hospitalized seniors to improve their nutrition. This study aimed to understand geriatric patients’ perceptions regarding meals in a common dining area versus at the bedside.

Methods

An exploratory qualitative study was conducted. Open-ended questions were asked of eight patients recruited from a geriatric rehabilitation unit where patients had a choice of meal location.

Results

Eating location was influenced by compliance with the perceived rules of the unit, physical and emotional well-being, and quarantine orders. Certain participants preferred eating in the common dining room where they had more assistance from hospital staff, a more attractive physical environment, and the opportunity to socialize. However, other participants preferred eating at their bedsides, feeling the quality of social interaction was poor in the dining room.

Conclusions

Participants’ experiences of, and preferences for, communal dining differed. If the benefits of communal dining are to be maximized, different experiences of this practice must be considered.

Peers and Obesity during Childhood and Adolescence: A Review of the Empirical Research on Peers, Eating, and Physical Activity

Obesity during childhood and adolescence is a growing problem in the United States, Canada, and around the world that leads to significant physical, psychological, and social impairment. In recent years, empirical research on factors that contribute to the development and maintenance of obesity has begun to consider peer experiences, such as peer rejection, peer victimization, and friendship. Peer experiences have been theoretically and empirically related to the “Big Two” contributors to the obesity epidemic, eating and physical activity, but there has not been a comprehensive review of the extant empirical literature. In this article, we review and synthesize the emerging theoretical and empirical literatures on peer experiences in relation to: (a) eating (food consumption and food selection); and (b) physical activity, during childhood and adolescence. A number of limitations and issues in the theoretical and empirical literatures are also discussed, along with future research directions. In conclusion, we argue that the involvement of children and adolescents’ peer networks in prevention and intervention efforts may be critical for promoting and maintaining positive behavioral health trajectories.

Development of eating behavior: biology and context

Eating is necessary for survival, gives great pleasure, and can be perturbed leading to undernutrition, overnutrition, and eating disorders. The development of feeding in humans relies on complex interplay between homeostatic mechanisms; neural reward systems; and child motor, sensory, and socioemotional capability. Furthermore, parenting, social influences, and the food environment influence the development of eating behavior. The rapid expansion of new knowledge in this field, from basic science to clinical and community-based research, is expected to lead to urgently needed research in support of effective, evidence-based prevention and treatment strategies for undernutrition, overnutrition, and eating disorders in early childhood. Using a biopsychosocial approach, this review covers current knowledge of the development of eating behavior from the brain to the individual child, taking into account important contextual influences.

Influence of peers and friends on children's and adolescents' eating and activity behaviors

Obesity during childhood and adolescence is a growing problem in the United States, Canada, and around the world that leads to significant physical, psychological, and social consequences. Peer experiences have been theoretically and empirically related to the "Big Two" contributors to the obesity epidemic, unhealthy eating and physical inactivity. In this article, we synthesize the empirical literature on the influence of peers and friends on youth's eating and physical activity. Limitations and issues in the theoretical and empirical literatures are also discussed, along with future research directions. In conclusion, we argue that the involvement of children's and adolescents' peer networks in prevention and intervention efforts may be critical for promoting and maintaining positive behavioral health trajectories. However, further theoretical and empirical work is needed to better understand the specific mechanisms underlying the effects of peers on youth's eating and physical activity.

Development and Reliability of the Mealtime Social Interaction Measure for Long-Term Care (MSILTC)

Mealtimes are important social events in retirement (RH) and long term care homes (LTC). This manuscript describes the development, refining and scaling of the MSILTC as well as inter-observer reliability. Two facilities provided access to their RH (n~100) and LTC (n~30-45) dining rooms. This observation-based tool captures both frequency and nature of interactions. Mealtime observations were carried out by trained researchers for development (n=13 tables), refinement (n=12 tables) scaling (n=17 tables) and reliability (n= 30 tables). Tablemate and staff level sub scores are calculated considering number of residents at the table and duration of the meal. Statistical analysis using Cohen’s kappa demonstrated that the tool possesses adequate reliability for capturing frequency of interaction among residents and staff [kappa 0.712 and 0.790 respectively]; reliability for nature of interaction was lower [kappa 0.590 and 0.441 respectively]. Construct validity testing is planned to complete the development of the MSILTC.

High-fat diet-induced obesity in animal models

Epidemiological studies have shown a positive relationship between dietary fat intake and obesity. Since rats and mice show a similar relationship, they are considered an appropriate model for studying dietary obesity. The present paper describes the history of using high-fat diets to induce obesity in animals, aims to clarify the consequences of changing the amount and type of dietary fats on weight gain, body composition and adipose tissue cellularity, and explores the contribution of genetics and sex, as well as the biochemical basis and the roles of hormones such as leptin, insulin and ghrelin in animal models of dietary obesity. The major factors that contribute to dietary obesity - hyperphagia, energy density and post-ingestive effects of the dietary fat - are discussed. Other factors that affect dietary obesity including feeding rhythmicity, social factors and stress are highlighted. Finally, we comment on the reversibility of high-fat diet-induced obesity.

The control of food intake of free-living humans: putting the pieces back together

The control of food intake has been studied using reductionism; by separately investigating environmental, physiological, and genetic variables. The general model of intake regulation attempts to reassemble the pieces into an organized whole. It postulates that intake is influenced by sets of both physiological factors which have negative feedback loops to intake and environmental factors which do not. Data and behavioral genetic analysis on a number of environmental, psychological, dietary, and social variables demonstrate that they have large impacts on the intake of free-living humans in their everyday environments and their magnitude and impact on intake are influenced by heredity. Recent evidence of built environment influences on activity and intake further indicate the profound influence of environmental circumstances on both intake and expenditure. A computer simulation of the general model of intake regulation demonstrates that the model predicts different maintained levels of intake and body weight depending upon the external environment and that change in the environment can produce new sustained levels. It is suggested that eating is influenced by a myriad of physiological and non-physiological factors and that total intake results from the integral of their influences. It is concluded that recombining the components broken down in the reductionistic process results in a functional whole that can well describe human behavior in natural environments. The paper represents an invited review by a symposium, award winner or keynote speaker at the Society for the Study of Ingestive Behavior [SSIB] Annual Meeting in Portland, July 2009.

Influence of environmental factors on food intake and choice of beverage during meals in teenagers: a laboratory study

Environmental conditions influence meal size in adults and children. Intake of sweet drinks could contribute significantly to energy intake and potentially affect body weight, particularly in young individuals. The objectives of the present study were to measure the lunch intake of food and drinks under controlled laboratory settings in teenagers and to compare the influence of different meal conditions. Normal-weight adolescents (fourteen males and fifteen females) participated in four standardised lunches, scheduled 1 week apart. The same popular items (meat dish, dessert, water, juice, soda) were served at all meals. Ad libitum intake was measured under four conditions: subjects ate alone; in groups; alone while viewing television; alone while listening to music. Visual analogue scales were used to assess pre- and post-meal hunger and thirst and meal palatability. Energy, solid food and fluid intake was different (significantly lower) only in the ‘eating in group’ condition, in spite of identical intensity of pre-meal hunger. More soda was consumed when participants were watching television, and more water was consumed while listening to music. Across all conditions, more soda than water was consumed. Post-meal ratings of hunger, thirst and palatability did not differ between conditions. We concluded that, in teenagers, a ‘social inhibition’ effect appears rather than the ‘social facilitation’ previously reported in adults. Although teenagers do not respond to the presence of television or another ‘distractor’ such as music by eating more, they do ingest more soda when the television is on. The social significance of meals, conditioned responses and habituation to ‘distractors’ may be different between adolescents and adults.

Influence of dietary restraint and environmental factors on meal size in normal-weight women. A laboratory study

In a previous study, we observed that the level of dietary restraint in normal-weight women moderated the stimulating effect of environmental stimuli on meal intake. The present study was designed to confirm and extend this observation. The influence of factors previously shown to affect meal size was investigated: presence of other people, television viewing and listening to radio. Two groups of 20 women were recruited, characterized by high versus low restraint. They participated in five standardised ad libitum lunches, under controlled laboratory conditions: subjects ate alone; in groups; listening to a detective story on the radio; watching television (no food cues); watching food advertisements on television. Lunches had identical menu (main dish and dessert) and were scheduled at 1-week intervals. Visual analogue scales were used to assess hunger, fullness and test-meal palatability. Repeated measures ANOVAs revealed no significant main effect of level of restraint and no interaction with meal conditions. Energy and main dish intakes were lower in the group meal condition than in the other four, which did not significantly differ. Group meals were followed by less intense fullness than the other conditions. These observations raise questions about the factors affecting social influence at meal times; gender, level of acquaintance and inhibitory norm are discussed. Our results also suggest that the intake stimulating effects of various external sources of distraction at meal time could vary in different populations.

Malnutrition and mealtime ambiance in nursing homes

Inadequate nutritional intake is the predominant cause of malnutrition in older persons. It is one of the most common and devastating conditions in nursing home residents. It is multifactorial and treatment or nutrition care plans should try to address the main causes. Such plans often include means to stimulate appetite to prevent or treat anorexia. One important stimulus, which can be modulated easily, is the meal ambiance. This article deals with the theory or mechanism behind this meal ambiance stimulus, discusses some study results, and makes practical recommendations.

Eating in larger groups increases food consumption

OBJECTIVE

To determine whether children's food consumption is increased by the size of the group of children in which they are eating.

DESIGN

Crossover study.

SETTING

University based preschool.

PARTICIPANTS

54 children, aged 2.5-6.5 years.

INTERVENTIONS

Each child ate a standardised snack in a group of three children, and in a group of nine children.

MAIN OUTCOME MEASURES

Amount each individual child consumed, in grams.

RESULTS

Amount eaten and snack duration were correlated (r = 0.71). The association between group size and amount eaten differed in the short (<11.4 min) versus the long (> or =11.4 min) snacks (p = 0.02 for the interaction between group size and snack duration). During short snacks, there was no effect of group size on amount eaten (16.7 (SD 11) g eaten in small groups vs 15.1 (6.6) g eaten in large groups, p = 0.42). During long snacks, large group size increased the amount eaten (34.5 (16) vs 26.5 (13.8), p = 0.02). The group size effect was partially explained by a shorter latency to begin eating, a faster eating rate and reduced social interaction in larger groups.

CONCLUSIONS

Children consumed 30% more food when eating in a group of nine children than when eating in a group of three children during longer snacks. Social facilitation of food consumption operates in preschool-aged children. The group size effect merits consideration in creating eating behaviour interventions.

Nutritional implications of patient–provider interactions in hospital settings: evidence from a within-subject assessment of mealtime exchanges and food intake in elderly patients

OBJECTIVE

To examine the nutritional implications of the interactions taking place between patients and care providers during mealtimes in hospital settings. Specifically, we tested research propositions that the amount and nature of interpersonal behaviours exchanged between patients and providers impact patients' food intake. These propositions were derived from prior evidence of social influences on eating behaviour and a well-established framework that identifies two fundamental modalities of human interaction: striving for mastery and power (agency) and efforts to promote union with others (communion).

DESIGN

In a within-subject naturalistic study, participants were observed on multiple meals (n=1477, 46.2 meals/participant on average), during which participants' and providers' agency- and communion-related behaviours and patients' protein and energy intake were recorded. Meal-level frequency and complementarity of patients' and providers' behaviours were computed to test research propositions.

SETTING

Dining room of a geriatric rehabilitation unit.

SUBJECTS

Thirty-two elderly patients (21 females, mean age:78.8, 95% CI: 76.4, 81.1).

RESULTS

Meal-level frequency of patient-provider exchanges (P=0.016) and patients' agency-related behaviours (P=0.029), as well as mutual reciprocation of patients' and providers' communion-related behaviours (P=0.015) on a given meal were positively linked to protein intake. Higher energy intake was found during meals where patients expressed more agency-related behaviours (P=0.029).

CONCLUSION

Results present evidence that the amount and nature of patient-provider interpersonal exchanges on a given meal influence the nutritional quality of food intake in hospitalized elderly. They provide insights into how to improve the design and delivery of routine care to this malnutrition-prone population.

SPONSORSHIP

This study was supported by the Canadian Institutes of Health Research (Operating grant to Laurette Dubé, Doctoral Fellowship to Catherine Paquet) the Fonds de la Recherche en santé du Québec and by the Danone Institute (Doctoral fellowship to Danielle St-Arnaud McKenzie).

Influence of physiological and subjective arousal on food intake in humans

OBJECTIVES

This study explored the influence of physiologic and subjective arousal on ambient factors of the food environment, such as the eating location, the presence of other people, sound, and time of day and on food intake. It was hypothesized that the influence of environmental stimuli on food intake would be mediated by arousal.

METHODS

College students were asked to wear heart rate monitors and to record their food intake in a 7-d diet diary. Subjective arousal (elation and excitement) and aspects of the eating environment were recorded for each meal occasion.

RESULTS

Results showed that subjective arousal seems to be related to food intake (P < 0.01) and appears to be affected by environmental stimuli such as the eating location (P < 0.01) and the number of people present (P < 0.01), but only small effects of some environmental stimuli on heart rate were found with higher average heart rates in restaurants (P < 0.05). No effects of heart rate on food intake were detected. Regression analyses failed to show arousal as a significant mediator between environmental stimuli and food intake.

CONCLUSION

It can be concluded that, for normal individuals in their everyday environment, ambient influences on food intake are not mediated by changes in arousal. However, the environment and the emotional state of the individual appear to play a role in the individual's eating behavior.

Effect of Family-Style Meals on Energy Intake and Risk of Malnutrition in Dutch Nursing Home Residents: A Randomized Controlled Trial

BACKGROUND

Social facilitation and meal ambiance have beneficial effects on food intake in healthy adults. Extrapolation to the nursing home setting may lead to less malnutrition among the residents. Therefore, we investigate the effect of family-style meals on energy intake and the risk of malnutrition in Dutch nursing home residents.

METHODS

In 2002 and 2003, a randomized controlled trial was conducted among 178 residents (mean age 77 years) in five Dutch nursing homes. Within each home, two wards were randomized into an intervention (n = 94) and a control group (n = 84). For 6 months, the intervention group received their meals family style, and the control group received the usual individual preplating services. Outcome measures were intakes of energy (kJ), carbohydrates (g), fat (g), and protein (g) and Mini Nutritional Assessment (MNA) score (0-30).

RESULTS

The change in daily energy intake between the control and intervention group differed significantly (991 kJ; 95% confidence interval [CI], 504-1479). The difference in intake of macronutrients was 29.2 g (95% CI, 13.5-44.9) for carbohydrate, 9.1 g (95% CI, 2.9-15.2) for fat, and 8.6 g (95% CI, 3.4-13.6) for protein. The percentage of residents in the intervention group classified by the MNA as malnourished decreased from 17% to 4%, whereas this percentage increased from 11% to 23% in the control group.

CONCLUSIONS

Family-style meals stimulate daily energy intake and protect nursing home residents against malnourishment. Therefore, replacement of the preplating meal services with family-style meals in nursing homes is recommended.

Meal duration mediates the effect of "social facilitation" on eating in humans

This experiment examined the 'time extension' explanation for the social facilitation effect, which is that people eat more as the number of co-eaters increases. Seventy male and 62 female participants ate a lunch consisting of pizza, cookies, and bottled water, alone or in (same-gender) groups of two or four and were given either 12 or 36 min in which to do so. The independent variables were gender, group size, and meal duration. The main dependent variable was amount consumed in the meal. The results showed that male participants ate more than did females, and participants eating the longer meal ate more than did those eating the shorter meal. However, the effect of group size was not significant. It was also the case that the amounts consumed by participants eating in two-person groups resembled one another to a greater extent than did of pairs of participants who ate alone or by participants in four-person groups. It was concluded that the results of the present paper provide strong support for the idea that the effect of group size on intake seen in previous studies is mediated by meal duration.

Food acceptability in field studies with US army men and women: relationship with food intake and food choice after repeated exposures

Laboratory data with single exposures showed that palatability has a positive relationship with food intake. The question addressed in this study is whether this relationship also holds over repeated exposures in non-laboratory contexts in more natural environments. The data were collected in four field studies, lasting 4-11 days with 307 US Army men and 119 Army women, and comprised 5791 main meals and 8831 snacks in total. Acceptability was rated on the nine point hedonic scale, and intake was registered in units of 1/4, 1/2, 3/4, or 1 or more times of the provided portion size. Correlation coefficients between individual acceptability ratings and intakes varied from 0.22 to 0.62 for the main meals (n=193-2267), and between 0.13 and 0.56 for the snacks (n=304-2967). The likelihood of choosing a meal for the second time was positively related to the acceptability rating of the meal when it was consumed for the first time. The results reinforce the importance of liking in food choice and food intake/choice behavior. However, the magnitude of the correlation coefficients between acceptability ratings and food intake suggest that environmental factors also have an important role in determining intake and choice.

A comparison of energy intake between eating positions in a NHS hospital—a pilot study

Malnutrition and the under-consumption of food in hospitals is prevalent and in UK hospitals, the consumption of meals is mainly a solitude event, despite evidence to show that eating in the presence of others can actually increase food intake. Dietary data were collected for three consecutive 24 h periods (n=13) from patients who consumed their meals either in bed, at the side of the bed or in the presence of others. Results show a significant increase (p<0.05) in the mean daily energy intake for those sitting around a table in the presence of others. Although a small pilot study, the results confirm the value of social facilitation in improving the under-consumption of food when in hospital.

The more food young adults are served, the more they overeat

Young and Nestle suggested that the increase in the portion size of food products evident in the United States during the past 20 years may be responsible for the epidemic of overweight and obesity. They based their conclusion on statistical correlations. The purpose of the present study was to provide experimental evidence to support their proposal. Cornell undergraduate students were given access to a buffet lunch on Monday, Wednesday, and Friday and were told this was a test of flavor enhancers. They were instructed to eat as much or as little as they wanted. On the same days of the following week, the subjects were divided into 3 groups. Each group was served either 100%, 125%, or 150% of the amount of food they had consumed the previous week. When larger amounts were served, significantly greater amounts of food were consumed. Each of the 4 foods that comprised the meal (soup, pasta, breadsticks, ice cream) increased significantly in proportion to the portion size. The data clearly support the hypothesis proposed by Young and Nestle and support the powerful role that environment plays in determining energy intake and potential increases in body weight.

Non food-related environmental stimuli induce increased meal intake in healthy women: comparison of television viewing versus listening to a recorded story in laboratory settings

The objective of the present study, performed under laboratory conditions, was to assess the impact of two non food-related environmental stimuli (television and auditory stimulus) on meal intake. Normal weight women (N = 48) ate lunch in the laboratory once a week for four weeks. All lunches were identical and included popular traditional foods, of which participants could eat ad libitum. The first and last lunches were eaten in the absence of the environmental stimuli (control conditions); in the other two tests, presented in random order, subjects ate while either watching television or listening to a recorded story. Energy intakes were determined for each meal, as were ratings of hunger, satiety and meal palatability. Subjects filled out the Three Factor Eating Questionnaire at the end of the meal series. Meal size was significantly larger in the presence of both environmental stimuli than in both control conditions (+11.6%, 280 kJ, p < 0.01). Television viewing induced a significant stimulation of intake, equal to, but not greater than the effect of the auditory stimulus. Ratings of hunger, satiety, and palatability were not significantly different between conditions, despite the differences in intake. These results suggest that environmental, non food-related stimuli could stimulate intake regardless of hunger-satiety or palatability conditions. Environmental stimulation of eating should be tested in other populations, eg subjects with weight control problems, and other conditions, e.g. free-living.