Effects of effort and social modeling on drinking in humans

Prevalence of and risk factors for thirst in the intensive care unit: An observational study

AIM AND OBJECTIVES

This study investigated the incidence of thirst and contributing factors in intensive care unit (ICU) patients by analysing differences in physiologic, psychological, and disease- and environment-related parameters in ICU patients with vs without thirst.

BACKGROUND

Little is known about the factors that influence thirst, and there are no standardised methods for identifying at-risk patients in the ICU. Previous studies generalised the risk of thirst in ICU patients because of a lack of data on relevant variables. Here, we examined the factors contributing to thirst based on symptom management theory.

DESIGN

Prospective descriptive design.

METHODS

Physiologic, psychological, disease-related and environment-related data were collected for 301 patients from 4 ICUs (medical, surgical, cardiac and emergency ICUs) of a hospital from 15 December 2017-10 July 2019 through a screening interview, questionnaires and from electronic medical records. The data were analysed with descriptive statistics, the t-test and chi-squared test, and by logistic regression. Binary stepwise logistic regression was used to identify thirst-associated factors. The findings are reported according to the STROBE checklist for cross-sectional studies.

RESULTS

In total, 210/301 (69.8%) ICU patients experienced thirst. Risk factors were nil per os order (odds ratio [OR] = 4.10, 95% confidence interval [CI]: 1.44-11.69), surgery (OR = 2.96, 95% CI: 1.11-7.93), high glucose (OR = 3.36, 95% CI: 1.01-11.17) and greater disease severity (OR = 1.13, 95% CI: 1.02-1.24).

CONCLUSION

Thirst is common in ICU patients. Timely detection of patients' thirst and identification of those at high risk by ICU nurses can ensure the implementation of effective and safe interventions.

RELEVANCE TO CLINICAL PRACTICE

The results of this study highlight the need to evaluate thirst symptoms in patients with severe disease and develop relief strategies for fasting, perioperative, and hyperglycaemic patients and others who are at high risk of thirst.

Does the relationship between alcohol retail environment and alcohol outcomes vary by depressive symptoms? Findings from a U.S. Survey of Black, Hispanic and White drinkers

AIMS

To assess whether associations between alcohol availability and consumption, drinking to drunkenness, and negative drinking consequences vary among individuals with elevated depressive symptoms.

METHODS

10,482 current drinkers in 2005-2015 National Alcohol Surveys (50.0% female; 74.4% White, 8.7% Black, 11.1% Hispanic). Elevated depressive symptoms was defined as having symptoms suggestive of major depressive disorder (above CES-D8/PHQ-2 cut-offs) versus no/sub-threshold symptoms (below cut-offs). Inverse probability of treatment weighted and covariate adjusted Poisson models with robust standard errors estimated associations of ZIP-code bar density and off-premise outlet density (locations/1,000 residents), elevated depressive symptoms, and their interaction with past-year volume consumed, monthly drinking to drunkenness, and negative drinking consequences. Models were then stratified by sex and race and ethnicity.

RESULTS

Overall, 13.7% of respondents had elevated depressive symptoms. Regarding density, the only statistically significant association observed was between off-premise density and volume consumed (rate ratio = 1.3, 95% confidence interval = 1.0, 1.7). Elevated depressive symptoms were associated with higher volume consumed, prevalence of drinking to drunkenness, and prevalence of negative consequences when controlling for off-premise density or bar density. However, there was no evidence of interaction between symptoms and density in the full sample nor among subgroups.

CONCLUSION

This study suggests that, while elevated depressive symptoms do not alter associations between alcohol availability and alcohol use and problems, they remain associated with these outcomes among past-year drinkers in a U.S. general population sample even when accounting for differential availability. Addressing depressive symptoms should be considered along with other policies to reduce population-level drinking and alcohol problems.

Organizational Food Environments: Advancing Their Conceptual Model

Understanding the complexity of the elements that constitute organizational food environments and their operating dynamics is essential to improving their healthiness. This study developed a conceptual model of organizational food environments. For this purpose, a comprehensive literature review was conducted, a first version of the conceptual model was prepared, a panel of experts was consulted, the model was improved, a second panel of experts was consulted, and the model was finalized. The model consists of four components (the institutional level, internal level of eating spaces, surroundings, and the decisional level) and 10 dimensions related to the institutional level and internal level of eating spaces (the availability, accessibility, affordability, quality, food and nutrition information, and promotion of foods, beverages, and culinary preparations and the availability, acceptability, convenience, ambience, and infrastructure of the eating space), as expressed in a graphical scheme. The conceptual model presented here offers innovative elements which contribute to understanding of the organizational food environment. It can guide the development of both assessment studies of food environments and interventions for their improvement.

Visible sugar : Salient sugar information impacts health perception of fruit juices but only when motivated to be responsible and not when motivated to enjoy

The present study explores when consumers recognize the high sugar content of fruit juice and refrain from choosing it for themselves or their families. Fruit juice may be typically perceived as a healthy drink, despite its often high sugar content. We investigate the role of salience of sugar information and enjoyment and responsibility goals in perception and choice of fruit juices. We argue that sugar information needs to be salient to prevent this health halo effect, but that consumers also need to be in a motivational state that promotes processing of this information. In three experiments (N = 801), we manipulate the salience of the sugar content using a salient sugar label (or no explicit sugar label) as well as the activation of different goals (to enjoy versus to be responsible, in the context of choices for self versus significant others). Utilising a newly designed fictitious juice brand, salient sugar labels are effective in significantly raising awareness of sugar content in study 1. Consumers primed for responsibility consider fruit juice with salient sugar information unhealthier as compared to those primed for enjoyment in study 2. Further, in study 3, parents primed for responsibility perceive fruit juice with salient sugar information as unhealthier and less appealing in comparison to parents primed for enjoyment. The effects of responsibility and enjoyment primes on health perceptions are stronger when people think of responsibility or enjoyment of food in the context of their families rather than themselves. We discuss implications for theorizing, beverage marketing, and public policy.

Nudges, Norms, or Just Contagion? A Theory on Influences on the Practice of (Non-)Sustainable Behavior

‘Nudging’ symbolizes the widespread idea that if people are only provided with the ‘right’ options and contextual arrangements, they will start consuming sustainably. Opposite to this individual-centered, top-down approach stand observations highlighting the ‘contagiousness’ of thoughts, emotions, and behaviors of reference groups or persons present in a decision-context. Tying in these two lines, this paper argues that nudging may sound promising and easily applicable, yet the social dynamics occurring around it can easily distort or nullify its effects. This argument stems from empirical evidence gained in an exploratory observation study conducted in a Swedish cafeteria (N = 1073), which included a ‘nudging’ treatment. In the study, people in groups almost unanimously all chose the same options. After rearranging the choice architecture to make a potentially sustainable choice easier, people stuck to this mimicking behavior—while turning to choose more the non-intended option than before. A critical reflection of extant literature leads to the conclusion that the tendency to mimic each other (unconsciously) is so strong that attempts to nudge people towards certain choices appear overwhelmed. Actions become ‘contagious’; so, if only some people stick to their (consumption) habits, it may be hard to induce more sustainable behaviors through softly changing choice architectures.

Altering the availability or proximity of food, alcohol, and tobacco products to change their selection and consumption

BACKGROUND

Overconsumption of food, alcohol, and tobacco products increases the risk of non-communicable diseases. Interventions to change characteristics of physical micro-environments where people may select or consume these products - including shops, restaurants, workplaces, and schools - are of considerable public health policy and research interest. This review addresses two types of intervention within such environments: altering the availability (the range and/or amount of options) of these products, or their proximity (the distance at which they are positioned) to potential consumers.

OBJECTIVES

1. To assess the impact on selection and consumption of altering the availability or proximity of (a) food (including non-alcoholic beverages), (b) alcohol, and (c) tobacco products.2. To assess the extent to which the impact of these interventions is modified by characteristics of: i. studies, ii. interventions, and iii.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, PsycINFO, and seven other published or grey literature databases, as well as trial registries and key websites, up to 23 July 2018, followed by citation searches.

SELECTION CRITERIA

We included randomised controlled trials with between-participants (parallel group) or within-participants (cross-over) designs. Eligible studies compared effects of exposure to at least two different levels of availability of a product or its proximity, and included a measure of selection or consumption of the manipulated product.

DATA COLLECTION AND ANALYSIS

We used a novel semi-automated screening workflow and applied standard Cochrane methods to select eligible studies, collect data, and assess risk of bias. In separate analyses for availability interventions and proximity interventions, we combined results using random-effects meta-analysis and meta-regression models to estimate summary effect sizes (as standardised mean differences (SMDs)) and to investigate associations between summary effect sizes and selected study, intervention, or participant characteristics. We rated the certainty of evidence for each outcome using GRADE.

MAIN RESULTS

We included 24 studies, with the majority (20/24) giving concerns about risk of bias. All of the included studies investigated food products; none investigated alcohol or tobacco. The majority were conducted in laboratory settings (14/24), with adult participants (17/24), and used between-participants designs (19/24). All studies were conducted in high-income countries, predominantly in the USA (14/24).Six studies investigated availability interventions, of which two changed the absolute number of different options available, and four altered the relative proportion of less-healthy (to healthier) options. Most studies (4/6) manipulated snack foods or drinks. For selection outcomes, meta-analysis of three comparisons from three studies (n = 154) found that exposure to fewer options resulted in a large reduction in selection of the targeted food(s): SMD -1.13 (95% confidence interval (CI) -1.90 to -0.37) (low certainty evidence). For consumption outcomes, meta-analysis of three comparisons from two studies (n = 150) found that exposure to fewer options resulted in a moderate reduction in consumption of those foods, but with considerable uncertainty: SMD -0.55 (95% CI -1.27 to 0.18) (low certainty evidence).Eighteen studies investigated proximity interventions. Most (14/18) changed the distance at which a snack food or drink was placed from the participants, whilst four studies changed the order of meal components encountered along a line. For selection outcomes, only one study with one comparison (n = 41) was identified, which found that food placed farther away resulted in a moderate reduction in its selection: SMD -0.65 (95% CI -1.29 to -0.01) (very low certainty evidence). For consumption outcomes, meta-analysis of 15 comparisons from 12 studies (n = 1098) found that exposure to food placed farther away resulted in a moderate reduction in its consumption: SMD -0.60 (95% CI -0.84 to -0.36) (low certainty evidence). Meta-regression analyses indicated that this effect was greater: the farther away the product was placed; when only the targeted product(s) was available; when participants were of low deprivation status; and when the study was at high risk of bias.

AUTHORS' CONCLUSIONS

The current evidence suggests that changing the number of available food options or altering the positioning of foods could contribute to meaningful changes in behaviour, justifying policy actions to promote such changes within food environments. However, the certainty of this evidence as assessed by GRADE is low or very low. To enable more certain and generalisable conclusions about these potentially important effects, further research is warranted in real-world settings, intervening across a wider range of foods - as well as alcohol and tobacco products - and over sustained time periods.

Altering the availability or proximity of food, alcohol, and tobacco products to change their selection and consumption

BACKGROUND

Overconsumption of food, alcohol, and tobacco products increases the risk of non-communicable diseases. Interventions to change characteristics of physical micro-environments where people may select or consume these products - including shops, restaurants, workplaces, and schools - are of considerable public health policy and research interest. This review addresses two types of intervention within such environments: altering the availability (the range and/or amount of options) of these products, or their proximity (the distance at which they are positioned) to potential consumers.

OBJECTIVES

1. To assess the impact on selection and consumption of altering the availability or proximity of (a) food (including non-alcoholic beverages), (b) alcohol, and (c) tobacco products.2. To assess the extent to which the impact of these interventions is modified by characteristics of: i. studies, ii. interventions, and iii.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, PsycINFO, and seven other published or grey literature databases, as well as trial registries and key websites, up to 23 July 2018, followed by citation searches.

SELECTION CRITERIA

We included randomised controlled trials with between-participants (parallel group) or within-participants (cross-over) designs. Eligible studies compared effects of exposure to at least two different levels of availability of a product or its proximity, and included a measure of selection or consumption of the manipulated product.

DATA COLLECTION AND ANALYSIS

We used a novel semi-automated screening workflow and applied standard Cochrane methods to select eligible studies, collect data, and assess risk of bias. In separate analyses for availability interventions and proximity interventions, we combined results using random-effects meta-analysis and meta-regression models to estimate summary effect sizes (as standardised mean differences (SMDs)) and to investigate associations between summary effect sizes and selected study, intervention, or participant characteristics. We rated the certainty of evidence for each outcome using GRADE.

MAIN RESULTS

We included 24 studies, with the majority (20/24) giving concerns about risk of bias. All of the included studies investigated food products; none investigated alcohol or tobacco. The majority were conducted in laboratory settings (14/24), with adult participants (17/24), and used between-participants designs (19/24). All studies were conducted in high-income countries, predominantly in the USA (14/24).Six studies investigated availability interventions, of which two changed the absolute number of different options available, and four altered the relative proportion of less-healthy (to healthier) options. Most studies (4/6) manipulated snack foods or drinks. For selection outcomes, meta-analysis of three comparisons from three studies (n = 154) found that exposure to fewer options resulted in a large reduction in selection of the targeted food(s): SMD -1.13 (95% confidence interval (CI) -1.90 to -0.37) (low certainty evidence). For consumption outcomes, meta-analysis of three comparisons from two studies (n = 150) found that exposure to fewer options resulted in a moderate reduction in consumption of those foods, but with considerable uncertainty: SMD -0.55 (95% CI -1.27 to 0.18) (low certainty evidence).Eighteen studies investigated proximity interventions. Most (14/18) changed the distance at which a snack food or drink was placed from the participants, whilst four studies changed the order of meal components encountered along a line. For selection outcomes, only one study with one comparison (n = 41) was identified, which found that food placed farther away resulted in a moderate reduction in its selection: SMD -0.65 (95% CI -1.29 to -0.01) (very low certainty evidence). For consumption outcomes, meta-analysis of 15 comparisons from 12 studies (n = 1098) found that exposure to food placed farther away resulted in a moderate reduction in its consumption: SMD -0.60 (95% CI -0.84 to -0.36) (low certainty evidence). Meta-regression analyses indicated that this effect was greater: the farther away the product was placed; when only the targeted product(s) was available; when participants were of low deprivation status; and when the study was at high risk of bias.

AUTHORS' CONCLUSIONS

The current evidence suggests that changing the number of available food options or altering the positioning of foods could contribute to meaningful changes in behaviour, justifying policy actions to promote such changes within food environments. However, the certainty of this evidence as assessed by GRADE is low or very low. To enable more certain and generalisable conclusions about these potentially important effects, further research is warranted in real-world settings, intervening across a wider range of foods - as well as alcohol and tobacco products - and over sustained time periods.

Nudging consumers towards healthier choices: a systematic review of positional influences on food choice

Nudging or ‘choice architecture’ refers to strategic changes in the environment that are anticipated to alter people’s behaviour in a predictable way, without forbidding any options or significantly changing their economic incentives. Nudging strategies may be used to promote healthy eating behaviour. However, to date, the scientific evidence has not been systematically reviewed to enable practitioners and policymakers to implement, or argue for the implementation of, specific measures to support nudging strategies. This systematic review investigated the effect of positional changes of food placement on food choice. In total, seven scientific databases were searched using relevant keywords to identify interventions that manipulated food position (proximity or order) to generate a change in food selection, sales or consumption, among normal-weight or overweight individuals across any age group. From 2576 identified articles, fifteen articles comprising eighteen studies met our inclusion criteria. This review has identified that manipulation of food product order or proximity can influence food choice. Such approaches offer promise in terms of impacting on consumer behaviour. However, there is a need for high-quality studies that quantify the magnitude of positional effects on food choice in conjunction with measuring the impact on food intake, particularly in the longer term. Future studies should use outcome measures such as change in grams of food consumed or energy intake to quantify the impact on dietary intake and potential impacts on nutrition-related health. Research is also needed to evaluate potential compensatory behaviours secondary to such interventions.

Environmental Strategies to Promote Food Intake in Older Adults: A Narrative Review

Aging is often accompanied by lower intakes of food energy and consequent negative effects on health. To some extent this is due to declines in physiological ability, including the sensory responsiveness to regulate food intake. Fortunately, environmental factors may still influence food intake in older adults. Factors such as social facilitation, modeling, and nutrition knowledge and skills have been shown to stimulate their food intake. While environmental factors such as the eating location, portion size, food presentation, and labeling are known to influence eating behavior, their effectiveness in stimulating food intake in older persons is not well delineated. It is suggested that improving the environmental stimuli that promote food intake is a viable strategy to overcome age-related declines in nutrient intakes. This strategy is so promising that further research is warranted.

Does salt increase thirst?

Our diet is believed to be overly rich in sodium, and it is commonly believed that sodium intake increases drinking. Hence the concern of a possible contribution of dietary sodium to beverage intake which in turn may contribute to obesity and ill health. Here we examine whether voluntary, acute intake of a sodium load, as occurs in routine eating and snacking, increases thirst and drinking. We find that after ingesting 3.5 or 4.4 g NaCl (men) and 1.9 or 3.7 g (women) on nuts during 15 minutes, there is no increase in thirst or drinking of freely available water in the following 2 h compared with eating similar amounts of sugared or unflavored nuts. This suggests that routine ingestion of boluses of salt (~30-40% of daily intake for men, ~ 20-40% for women) does not increase drinking. Methodological concerns such as about nuts as vehicle for sodium suggest further research to establish the generalizability of this unexpected result.

Ad libitum fluid consumption via self- or external administration

CONTEXT

During team athletic events, athletic trainers commonly provide fluids with water bottles. When a limited number of water bottles exist, various techniques are used to deliver fluids.

OBJECTIVE

To determine whether fluid delivered via water-bottle administration influenced fluid consumption and hydration status.

DESIGN

Crossover study.

SETTING

Outdoor field (22.2°C ± 3.5°C).

PATIENTS OR OTHER PARTICIPANTS

Nineteen participants (14 men, 5 women, age = 30 ± 10 years, height = 176 ± 8 cm, mass = 72.5 ± 10 kg) were recruited from the university and local running clubs.

INTERVENTION(S)

The independent variable was fluid delivery with 3 levels: self-administration with mouth-to-bottle direct contact (SA-DC), self-administration with no contact between mouth and bottle (SA-NC), and external administration with no contact between the mouth and the bottle (EA-NC). Participants warmed up for 10 minutes before completing 5 exercise stations, after which an ad libitum fluid break was given, for a total of 6 breaks.

MAIN OUTCOME MEASURE(S)

We measured the fluid variables of total volume consumed, total number of squirts, and average volume per squirt. Hydration status via urine osmolality and body-mass loss, and perceptual variables for thirst and fullness were recorded. We calculated repeated-measures analyses of variance to assess hydration status, fluid variables, and perceptual measures to analyze conditions across time.

RESULTS

The total volume consumed for EA-NC was lower than for SA-DC (P = .001) and SA-NC (P = .001). The total number of squirts for SA-DC was lower than for SA-NC (P = .009). The average volume per squirt for EA-NC was lower than for SA-DC (P = .020) and SA-NC (P = .009). Participants arrived (601.0 ± 21.3 mOsm/L) and remained (622.3 ± 38.3 mOsm/L) hydrated, with no difference between conditions (P = .544); however, the EA-NC condition lost more body mass than did the SA-DC condition (P = .001). There was no main effect for condition on thirst (P = .147) or fullness (P = .475).

CONCLUSIONS

External administration of fluid decreased total volume consumed via a decreased average volume per squirt. The SA-DC method requires fewer squirts within a specific time frame. Fluid breaks every 15 minutes resulted in maintenance of euhydration; however, loss of body mass was influenced by fluid administration. Athletic trainers should avoid external administration to promote positive hydration behaviors. When fluid is self-administered, individual bottles may be the best clinical practice because more volume can be consumed per squirt.

Half full or empty: cues that lead wine drinkers to unintentionally overpour

Wine drinkers often pour their own wine, but is the amount they pour influenced by the shape of the glass, the color of the wine, or how they pour? Building on research involving visual illusions and haptic cues, an exploratory field study shows that while wine drinkers typically poured 3.95 fl. oz. of wine into a standard baseline (10 fl. oz.) glass, they poured 11.9% more into a wider glass, 9.2% more when the wine was white (the low contrast with the glass makes it difficult to see), and 12.2% more when the wine glass was held in their hand rather than sitting on the table. Using narrower wine glasses and not pouring while holding one's glass may be steps toward modestly reducing the amount of wine a social drinker pours and drinks.

A review of visual cues associated with food on food acceptance and consumption

Several sensory cues affect food intake including appearance, taste, odor, texture, temperature, and flavor. Although taste is an important factor regulating food intake, in most cases, the first sensory contact with food is through the eyes. Few studies have examined the effects of the appearance of a food portion on food acceptance and consumption. The purpose of this review is to identify the various visual factors associated with food such as proximity, visibility, color, variety, portion size, height, shape, number, volume, and the surface area and their effects on food acceptance and consumption. We suggest some ways that visual cues can be used to increase fruit and vegetable intake in children and decrease excessive food intake in adults. In addition, we discuss the need for future studies that can further establish the relationship between several unexplored visual dimensions of food (specifically shape, number, size, and surface area) and food intake.

Behavioural strategies to control the amount of food selected and consumed

Several factors within the food environment may stimulate overconsumption. The present study aimed to (1) identify behavioural strategies to cope with this environment to control the amount of food consumed, (2) examine the feasibility and usefulness of the strategies, and (3) evaluate the association between the strategies and body mass index (BMI). After the literature was screened for evidence of factors that contribute to the consumption of large amounts of food, 32 behavioural strategies were identified to overcome these influences (study 1). Subjectively reported feasibility and usefulness of the 32 behavioural strategies in weight management were explored using a pretest post-test study (study 2: n = 52). Additionally, two cross-sectional questionnaire studies (study 3a: n = 120 and study 3b: n = 278) were conducted to evaluate the association between the 32 behavioural strategies and BMI. The strategies were subjectively reported as feasible and useful in weight management. Frequent use of strategies discriminated non-overweight from overweight individuals, but did not discriminate overweight from obese individuals. In conclusion, the findings provided preliminary evidence for the acceptability and validity of the strategies. The effectiveness of the strategies for controlling the amount consumed should be further investigated, especially in overweight and obese participants.

Thirst in critically ill patients: from physiology to sensation

Critically ill patients often report distressful episodes of severe thirst, but the complex biochemical, neurohormonal mechanisms that regulate this primal sensation still elude clinicians. The most potent stimuli for thirst are subtle increases in plasma osmolality. These minute changes in osmolality stimulate central osmoreceptors to release vasopressin (also known as antidiuretic hormone). Vasopressin in turn acts on the kidneys to promote the reabsorption of water to correct the increased osmolality. If this compensatory mechanism fails to decrease osmolality, then thirst is triggered to motivate drinking. In contrast, thirst induced by marked volume loss, or hypovolemic thirst, is subject to the tight osmoregulation of the renin-angiotensin aldosterone system and accompanying adrenergic agonists. Understanding the essential role that thirst plays in salt and water regulation can provide clinicians with a better appreciation for the complex physiology that underlies this intense sensation.

Does food marketing need to make us fat? A review and solutions

Food marketing is often singled out as the leading cause of the obesity epidemic. The present review examines current food marketing practices to determine how exactly they may be influencing food intake, and how food marketers could meet their business objectives while helping people eat healthier. Particular attention is paid to the insights provided by recently published studies in the areas of marketing and consumer research, and those insights are integrated with findings from studies in nutrition and related disciplines. The review begins with an examination of the multiple ways in which 1) food pricing strategies and 2) marketing communication (including branding and food claims) bias food consumption. It then describes the effects of newer and less conspicuous marketing actions, focusing on 3) packaging (including the effects of package design and package-based claims) and 4) the eating environment (including the availability, salience, and convenience of food). Throughout, this review underscores the promising opportunities that food manufacturers and retailers have to make profitable "win-win" adjustments to help consumers eat better.

Nudge to nobesity I: Minor changes in accessibility decrease food intake

Very small but cumulated decreases in food intake may be sufficient to erase obesity over a period of years. We examine the effect of slight changes in the accessibility of different foods in a pay-by-weight-of-food salad bar in a cafeteria serving adults for the lunch period. Making a food slightly more difficult to reach (by varying its proximity by about 10 inches) or changing the serving utensil (spoon or tongs) modestly but reliably reduces intake, in the range of 8–16%. Given this effect, it is possible that making calorie-dense foods less accessible and low-calorie foods more accessible over an extended period of time would result in significant weight loss.

Relationships between human thirst, hunger, drinking, and feeding

There is a widely held view that hunger prompts feeding to ensure energy needs are met, while thirst cues drinking to address hydration requirements. However, recent changes in the nature of the food supply and eating patterns have raised questions about the functionality of these relationships with respect to maintaining energy balance. The increasing consumption of energy-yielding beverages and foods with diluted energy density, through the use of ingredients such as high-intensity sweeteners and fat replacers, poses new challenges to presumed homeostatic energy regulatory mechanisms. This review draws on findings from a recent observational study and other published evidence to explore whether shifts of food composition and use patterns may be disrupting relationships between thirst, hunger, drinking, and eating, resulting in positive energy balance (e.g., drinking low satiety, energy-yielding beverages in response to hunger). The observational study entailed collecting hourly appetitive ratings and dietary recalls from 50 adults for seven consecutive days. These data reveal a clear bimodal daily hunger pattern, whereas thirst is stronger and more stable throughout the day. Further, approximately 75% of fluid intake occurs peri-prandially, with the majority derived from energy-yielding beverages. While there is published evidence that drinking is responsive to feeding, support for the view that drinking is the more tightly regulated behavior is stronger. Our data indicates that, due to a number of plausible factors, neither absolute values nor changes of hunger or thirst are strong predictors of energy intake. However, it is proposed that stable, high thirst facilitates drinking, and with the increased availability and use of energy-yielding beverages that have low satiety properties, can promote positive energy balance. There are marked individual differences in mean daily hunger and thirst ratings with unknown implications for energy balance.

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 ambience on food intake and food choice

Eating takes place in a context of environmental stimuli known as ambience. Various external factors such as social and physical surroundings, including the presence of other people and sound, temperature, smell, color, time, and distraction affect food intake and food choice. Food variables such as the temperature, smell, and color of the food also influence food intake and choice differently. However, the influence of ambience on nutritional health is not fully understood. This review summarizes the research on ambient influences on food intake and food choice. The literature suggests that there are major influences of ambience on eating behavior and that the magnitude of the effect of ambience may be underestimated. Changes in intake can be detected with different levels of the number of people present, food accessibility, eating locations, food color, ambient temperatures and lighting, and temperature of foods, smell of food, time of consumption, and ambient sounds. It is suggested that the manipulation of these ambient factors as a whole or individually may be used therapeutically to alter food intake and that more attention needs to be paid to ambience in nutrition-related research.

ENVIRONMENTAL FACTORS THAT INCREASE THE FOOD INTAKE AND CONSUMPTION VOLUME OF UNKNOWING CONSUMERS

Package size, plate shape, lighting, socializing, and variety are only a few of the environmental factors that can influence the consumption volume of food far more than most people realize. Although such environmental factors appear unrelated, they generally influence consumption volume by inhibiting consumption monitoring and by suggesting alternative consumption norms. For researchers, this review suggests that redirecting the focus of investigations to the psychological mechanisms behind consumption will raise the profile and impact of research. For health professionals, this review underscores how small structural changes in personal environments can reduce the unknowing overconsumption of food.

History of food acceptance research in the US Army

The history of food acceptance research by the US Army in Chicago and Natick is reviewed. The review covers the staff of the two research centers, the research programs, and the significant accomplishments of the Army laboratories from the 1940s to the present. Accomplishments begin with the development of the nine-point hedonic scale, and the development of the first Food Acceptance Laboratory. Further accomplishments include studies of sensory psychophysics, food preferences, food choice and food intake. The laboratories designed methods and conducted research on the role of consumer variables in the acceptance of food products and food service systems. Recent work has focused on new scaling approaches, the role of contextual factors and the importance of product expectations. Throughout the period of the review, the Army research has examined the relationship of laboratory acceptance to field acceptance, and the relationship of acceptance to intake.