I'm watching you. Awareness that food consumption is being monitored is a demand characteristic in eating-behaviour experiments

The role of perceived negative partner behavior in daily snacking behavior: A dynamical systems approach

Past work suggested that psychological stress, especially in the context of relationship stress, is associated with increased consumption of energy-dense food and when maintained for long periods of time, leads to adverse health consequences. Furthermore, this association is moderated by a variety of factors, including emotional over-eating style. That being said, few work utilized a dynamical system approach to understand the intraindividual and interindividual fluctuations within this process. The current study utilized a 14-day daily diary study, collected between January-March 2020, where participants reported their partner's negative relationship behavior and their own snacking behavior. A differential equation model was applied to the daily dairy data collected. Results showed that snacking behavior followed an undamped oscillator model while negative relationship behavior followed a damped coupled oscillator model. In other words, snacking behavior fluctuated around an equilibrium but was not coupled within dyadic partners. Negative relationship behavior fluctuated around an equilibrium and was amplified over time, coupled within dyadic partners. Furthermore, we found a two-fold association between negative relationship behavior and snacking: while the association between the displacement of negative relationship behavior and snacking was negative, change in negative relationship behavior and snacking were aligned. Thus, at any given time, one's snacking depends both on the amount of negative relationship behaviors one perceives and the dynamical state a dyad is engaging in (i.e., whether the negative relationship behavior is "exacerbating" or "resolving"). This former association was moderated by emotional over-eating style and the latter association was not. The current findings highlight the importance of examining dynamics within dyadic system and offers empirical and methodological insights for research in adult relationships.

Body dissatisfaction and beyond: Investigating attitudes towards calorie labels on UK food menus

In 2022 the British government made calorie labels on menus a legal requirement to encourage healthier food choices while dining out. Yet, little research has explored perceptions of calorie labels on menus in the United Kingdom or tested whether there may be groups of people vulnerable to potential negative effects of calorie labels, such as those with body dissatisfaction. This between-subjects, convergent mixed-methods study addressed these enquiries. Participants were 562 adults who completed an online survey where hypothetical food orders were made from a menu. The study found that participants who viewed a menu with calorie labels ordered fewer calories. Quantitative results did not find that participants with higher levels of body dissatisfaction were at significantly greater odds of using calorie labels to order fewer calories. However, our qualitative (thematic) analysis revealed that experiences of calorie labels could be shaped by body image concerns. Themes further drew on how calorie labels were empowering, but there were also concerns about their oversimplicity. Findings are discussed in relation to implications for future calorie labelling policies. Given the inconsistent findings amongst the limited amount of literature investigating the role of body dissatisfaction in how calorie labels are used, future research is crucial. In the meantime, as a cautionary measure, clinicians involved in supporting individuals with body or food-related concerns should be aware of the challenges their clients may experience in facing calorie labels on menus when dining out.

Unit size influences ad libitum intake in a snacking context via eating rate

Geometric and textural properties of food, like unit size, have previously been shown to influence energy intake. While mechanism(s) driving this effect are unclear, unit size may relate to intake by affecting eating microstructure (e.g., eating rate, bite size). In a randomized crossover study, we investigated relationships between unit size, eating microstructure, and intake. Adults (n = 75, 75% women) consumed an ad libitum snack three times in our laboratory. This snack was a 70-g portion (∼2.5 servings) of one of three sizes of pretzel (small, medium, large). Intake was measured in grams by difference in weight before and after the snack. Each session was video recorded to measure eating microstructure; snack duration (min) and number of bites were annotated and used to calculate mean eating rate (g/min) and mean bite size (g/bite). Results revealed unit size influenced intake (grams and kcal; both p's ≤ 0.001), such that participants consumed 31% and 22% more of the large pretzels (16.9 ± 2.3 g) compared to the small (12.9 ± 2.3 g) and medium sizes (13.8 ± 2.3 g), respectively. Unit size also influenced eating rate and bite size (both p's < 0.001); the largest pretzel size yielded the fastest eating rate and largest mean bite size. Further analysis revealed that after accounting for eating microstructure, the effects of unit size on intake were no longer significant, suggesting eating microstructure was driving these effects. Together, these findings indicate that unit size influences intake by affecting eating microstructure and that food properties like unit size can be leveraged to moderate snack intake.

Associations between everyday exposure to food marketing and hunger and food craving in adults: An ecological momentary assessment study

Food marketing in television and digital media negatively affects appetitive sensations and eating behaviour in children, but effects are less well understood for outdoor food advertising and adults. This research used Ecological Momentary Assessment (EMA) to explore associations between exposures to food advertising in various contexts (television, digital, outdoors) and adults' hunger and craving for highly advertised food categories. Over one week, participants provided ratings of cravings for types of food (fast food, soft drinks, snacks/confectionery, other) and hunger on a smartphone app up to six times per day when they saw a food advertisement (reactive assessment) and at random intervals (random assessment). Fifty-four participants (70.4 % female; 21.24 ± 3.84 years) provided 1223 assessments (24.7 % reactive, 75.3 % random). Data were analysed in R using multilevel multivariable linear regression models. Participants reported feeling hungrier (X2(1) = 5.85, p = .016, ΔAIC = 3.9) and having stronger cravings (X2(1) = 20.64, p < .001, ΔAIC = 318.6) after seeing food advertisements vs. random assessments. This was driven by greater hunger following television advertising exposure vs. random assessments (β = 1.58, SE = 0.61, p = .010, 95 %CIs 0.38 to 2.78), food advertising via digital devices or outdoors was not associated with hunger. Participants experienced stronger craving after seeing a food advertisement on television (β = 0.52, SE = 0.19, p = .006, 95 %CIs 0.15 to 0.89), outdoors (β = 0.39, SE = 0.12, p < .001, 95 % CIs 0.16 to 0.62) and in digital media (β = 0.36, SE = 0.14, p = .012, 95 % CIs 0.08 to 0.64), vs. random assessments. Cravings were (largely) specific to the advertised food category. EMA can be effective for assessing food marketing associations in adults. The current study provides evidence that food marketing is associated with hunger and craving in adults, which may, with replication, have implications for public health policy.

Variety and portion size combine to increase food intake at single-course and multi-course meals

Increases in food variety and portion size independently promote intake. Little is known about how these effects combine or how they depend on meal structure. In two randomized crossover experiments, once a week for four weeks, women ate a lunch meal that was varied in two properties: variety (low: three bowls of the favorite dish vs. high: three bowls, each with a different main dish) and portion size (small: 450 g vs. large: 600 g). In Experiment 1 (n = 42), dishes were served simultaneously and in Experiment 2 (n = 49), dishes were served sequentially over three courses. At each meal, the primary outcome of food intake was measured; additionally, we measured sensory-specific satiety (SSS; the relative hedonic decline of a food as it is eaten). In Experiment 1 (simultaneous structure) variety and portion size did not interact (p = 0.72) but both independently increased intake; participants consumed 15 ± 7 g more at meals with high variety compared to low and 57 ± 7 g more from large portions compared to small (both p < 0.03). Similarly, in Experiment 2 (sequential structure) variety and portion size did not interact (p = 0.99) but participants consumed 30 ± 8 g more at high-variety meals and 51 ± 8 g more from large portions (both p < 0.001). SSS was not influenced by portion size in either experiment (both p > 0.16) or by variety in Experiment 1 (p = 0.58), but SSS was smaller at high-variety meals in Experiment 2 (p = 0.001). Thus, variety and large portions promoted greater food intake for a similar or smaller hedonic decline, indicating these effects were facilitated by delayed SSS. At meals with either a simultaneous or sequential structure, high variety and large portions combined to increase intake, suggesting that these common properties act together to promote overconsumption.

Technology to Automatically Record Eating Behavior in Real Life: A Systematic Review

To monitor adherence to diets and to design and evaluate nutritional interventions, it is essential to obtain objective knowledge about eating behavior. In most research, measures of eating behavior are based on self-reporting, such as 24-h recalls, food records (food diaries) and food frequency questionnaires. Self-reporting is prone to inaccuracies due to inaccurate and subjective recall and other biases. Recording behavior using nonobtrusive technology in daily life would overcome this. Here, we provide an up-to-date systematic overview encompassing all (close-to) publicly or commercially available technologies to automatically record eating behavior in real-life settings. A total of 1328 studies were screened and, after applying defined inclusion and exclusion criteria, 122 studies were included for in-depth evaluation. Technologies in these studies were categorized by what type of eating behavior they measure and which type of sensor technology they use. In general, we found that relatively simple sensors are often used. Depending on the purpose, these are mainly motion sensors, microphones, weight sensors and photo cameras. While several of these technologies are commercially available, there is still a lack of publicly available algorithms that are needed to process and interpret the resulting data. We argue that future work should focus on developing robust algorithms and validating these technologies in real-life settings. Combining technologies (e.g., prompting individuals for self-reports at sensed, opportune moments) is a promising route toward ecologically valid studies of eating behavior.

Human nutritional intelligence underestimated? Exposing sensitivities to food composition in everyday dietary decisions

The social and cultural significance of food is woven into every aspect of our dietary behaviour, and it contributes to our complex interaction with food. To find order within this complexity scientists often look for dietary 'universals' - phenomena or basic principles that guide our food choice and meal size, irrespective of wider context. One such idea is that taste characteristics provide a signal for dietary composition (e.g., sweet taste signals carbohydrate). Others have suggested that behaviour is guided by learning and is based on associations that form between the flavour of a food and its post-ingestive effects. Despite a large body of research, evidence supporting both processes is equivocal, leading some to conclude that humans are largely indifferent to food composition. Here, we argue that human abilities to gauge the nutritional composition or value of food have been underestimated, and that they can be exposed by embracing alternative methods, including cross-cultural comparisons, large nutrition surveys, and the use of virtual portion-selection tools. Our group has focused on assessments of food choice and expected satiety, and how comparisons across everyday foods can reveal non-linear relationships with food energy density, and even the potential for sensitivity to micronutrient composition. We suggest that these abilities might reflect a complex form of social learning, in which flavour-nutrient associations are not only formed but communicated and amplified across individuals in the form of a cuisine. Thus, rather than disregarding sociocultural influences as extraneous, we might reimagine their role as central to a process that creates and imbues a 'collective dietary wisdom.' In turn, this raises questions about whether rapid dietary, technological, and cultural change disrupts a fundamental process, such that it no longer guarantees a 'nutritional intelligence' that confers benefits for health.

Portion-control tableware differentially impacts eating behaviour in women with and without overweight

Portion control tableware has been described as a potentially effective approach for weight management, however the mechanisms by which these tools work remain unknown. We explored the processes by which a portion control (calibrated) plate with visual stimuli for starch, protein and vegetable amounts modulates food intake, satiety and meal eating behaviour. Sixty-five women (34 with overweight/obesity) participated in a counterbalanced cross-over trial in the laboratory, where they self-served and ate a hot meal including rice, meatballs and vegetables, once with a calibrated plate and once with a conventional (control) plate. A sub-sample of 31 women provided blood samples to measure the cephalic phase response to the meal. Effects of plate type were tested through linear mixed-effect models. Meal portion sizes (mean ± SD) were smaller for the calibrated compared with the control plate (served: 296 ± 69 vs 317 ± 78 g; consumed: 287 ± 71 vs 309 ± 79 g respectively), especially consumed rice (69 ± 24 vs 88 ± 30 g) (p < 0.05 for all comparisons). The calibrated plate significantly reduced bite size (3.4 ± 1.0 vs 3.7 ± 1.0 g; p < 0.01) in all women and eating rate (32.9 ± 9.5 vs 33.7 ± 9.2 g/min; p < 0.05), in lean women. Despite this, some women compensated for the reduced intake over the 8 h following the meal. Pancreatic polypeptide and ghrelin levels increased post-prandially with the calibrated plate but changes were not robust. Plate type had no influence on insulin, glucose levels, or memory for portion size. Meal size was reduced by a portion-control plate with visual stimuli for appropriate amounts of starch, protein and vegetables, potentially because of the reduced self-served portion size and the resulting reduced bite size. Sustained effects may require the continued use of the plate for long-term impact.

Downsizing food: a systematic review and meta-analysis examining the effect of reducing served food portion sizes on daily energy intake and body weight

Portion sizes of many foods have increased over time. However, the size of effect that reducing food portion sizes has on daily energy intake and body weight is less clear. We used a systematic review methodology to identify eligible articles that used an experimental design to manipulate portion size served to human participants and measured energy intake for a minimum of 1 d. Searches were conducted in September 2020 and again in October 2021. Fourteen eligible studies contributing eighty-five effects were included in the primary meta-analysis. There was a moderate-to-large reduction in daily energy intake when comparing smaller v. larger portions (Standardised Mean Difference (SMD) = -0·709 (95 % CI: -0·956, -0·461), approximately 235 kcal (983·24 kJ)). Larger reductions to portion size resulted in larger decreases in daily energy intake. There was evidence of a curvilinear relationship between portion size and daily energy intake; reductions to daily energy intake were markedly smaller when reducing portion size from very large portions. In a subset of studies that measured body weight (four studies contributing five comparisons), being served smaller v. larger portions was associated with less weight gain (0·58 kg). Reducing food portion sizes may be an effective population-level strategy to prevent weight gain.

Eating rate and bite size were related to food intake across meals varying in portion size: A randomized crossover trial in adults

Serving larger portions leads to increased food intake, but behavioral factors that influence the magnitude of this portion size effect have not been well characterized. We investigated whether measures of eating microstructure such as eating rate and bite size moderated the portion size effect. We also explored how sensory-specific satiety (SSS; the relative hedonic decline of a food as it is eaten) was affected by eating microstructure and larger portions. In a randomized crossover design, 44 adults aged 18-68 y (66% women; 46% with overweight and obesity) ate lunch in the laboratory once a week for 4 weeks. The meal consisted of pasta that was varied in portion size (400, 500, 600, or 700 g) and 700 g of water. Meals were video-recorded to assess bite count and meal duration, which were used to calculate mean eating rate (g/min) and mean bite size (g/bite). At each meal participants also completed an assessment of SSS. The results showed that as larger portions were served, meal intake increased in a curvilinear manner (p < 0.0001). Measures of eating microstructure did not moderate the portion size effect but were related to intake across all portions; faster eating rate, larger bite size, higher bite count, and longer meal duration were associated with greater consumption at all meals (all p < 0.0001). SSS was not influenced by any measure of eating microstructure or by portion size (all p > 0.10). In summary, the portion size effect was not moderated by eating microstructure, but relatively faster eating rates and larger bite sizes at meals, along with large portions, combined to increase food intake.

Development and validation of a new methodological platform to measure behavioral, cognitive, and physiological responses to food interventions in real time

To fully understand the causes and mechanisms involved in overeating and obesity, measures of both cognitive and physiological determinants of eating behavior need to be integrated. Effectively synchronizing behavioral measures such as meal micro-structure (e.g., eating speed), cognitive processing of sensory stimuli, and metabolic parameters, can be complex. However, this step is central to understanding the impact of food interventions on body weight. In this paper, we provide an overview of the existing gaps in eating behavior research and describe the development and validation of a new methodological platform to address some of these issues. As part of a controlled trial, 76 men and women self-served and consumed food from a buffet, using a portion-control plate with visual stimuli for appropriate amounts of main food groups, or a conventional plate, on two different days, in a random order. In both sessions participants completed behavioral and cognitive tests using a novel methodological platform that measured gaze movement (as a proxy for visual attention), eating rate and bite size, memory for portion sizes, subjective appetite and portion-size perceptions. In a sub-sample of women, hormonal secretion in response to the meal was also measured. The novel platform showed a significant improvement in meal micro-structure measures from published data (13 vs. 33% failure rate) and high comparability between an automated gaze mapping protocol vs. manual coding for eye-tracking studies involving an eating test (ICC between methods 0.85; 90% CI 0.74, 0.92). This trial was registered at Clinical Trials.gov with Identifier NCT03610776.

Boredom proneness, interoception, and emotional eating

Emotional eating is associated with weight gain and difficulty losing weight during weight loss interventions. Theoretical and empirical work suggest boredom may be an important predictor of problematic eating behaviors. Yet, little work has examined the role of boredom in emotional eating. Further, individual differences in the ability to recognize internal cues (i.e., interoception) may alter the impact of boredom on emotional eating. This study hypothesized that boredom proneness would predict unique variance in emotional eating after accounting for negative and positive affect, and that the association between boredom proneness and emotional eating would be stronger among those with poorer interoceptive ability compared to those with better interoceptive ability. Hypotheses were tested in two large samples using multiple linear regression. Participants aged 18-65 were recruited from MTurk (n = 365; 59.2% female) and an undergraduate research pool (n = 461; 52.9% female). Participants completed self-report measures: Boredom Proneness Scale; Dutch Eating Behavior Questionnaire- Emotional Eating; Multidimensional Assessment of Interoceptive Awareness-2; Intuitive Eating Scale-2- Reliance on Hunger and Satiety Cues; and Positive and Negative Affect Schedule. Boredom proneness was a significant predictor of emotional eating in both samples, even accounting for the broad dimensions of negative and positive affect (ps < .001). Interoception did not moderate the association between boredom proneness and emotional eating in either sample (ps > .05), but was an independent predictor of emotional eating (ps < .001). Boredom proneness and interoceptive ability may warrant attention as targets in the prevention and treatment of emotional eating. Future work should continue exploring different emotion categories and different facets of interoception in emotional eating, as well as examine novel mechanisms that could inform intervention efforts.

Calorie reformulation: a systematic review and meta-analysis examining the effect of manipulating food energy density on daily energy intake

BACKGROUND

Dietary energy density is thought to be a contributor to obesity, but the extent to which different magnitudes and types of reductions to food energy density decreases daily energy intake is unclear. The primary objective was to systematically review and meta-analyse experimental studies that have examined the effect that manipulating energy density of food has on total daily energy intake. Secondary objectives were to examine moderators of the effect that altering energy density has on daily energy intake and effects on body weight.

METHODS

A systematic review and multi-level meta-analysis of studies on human participants that used an experimental design to manipulate the energy density of foods served and measured energy intake for a minimum of 1 day.

RESULTS

Thirty-one eligible studies sampling both children (n = 4) and adults (n = 27) contributed 90 effects comparing the effect of higher vs. lower energy density of served food on daily energy intake to the primary meta-analysis. Lower energy density of food was associated with a large decrease in daily energy intake (SMD = - 1.002 [95% CI: - 0.745 to - 1.266]). Findings were consistent across studies that did vs. did not manipulate macronutrient content to vary energy density. The relation between decreasing energy density and daily energy intake tended to be strong and linear, whereby compensation for decreases to energy density of foods (i.e. by eating more at other meals) was minimal. Meta-analysis of (n = 5) studies indicated that serving lower energy dense food tended to be associated with greater weight loss than serving higher energy dense food, but this difference was not significant (- 0.7 kg difference in weight change, 95% CIs: - 1.34, 0.04).

CONCLUSIONS

Decreasing the energy density of food can substantially reduce daily energy intake and may therefore be an effective public health approach to reducing population level energy intake.

TRIAL REGISTRATION

Registered on PROSPERO ( CRD42020223973 ).

The Satiation Framework: Exploring processes that contribute to satiation

Satiation has been described as a process that leads to the termination of eating and controls meal size. However, studies have shown that the termination of eating can be influenced by multiple behavioral and biological processes over the course of a meal as well as those related to the context in which the meal is consumed. To expand understanding of how individuals experience satiation during a meal, we recently developed the Reasons Individuals Stop Eating Questionnaire (RISE-Q). The development of the RISE-Q revealed five distinct factors reported to contribute to meal termination: Planned Amount, Self-Consciousness, Decreased Food Appeal, Physical Satisfaction, and Decreased Priority of Eating. Thus, we define satiation as a series of dynamic processes that emerge over the course of a meal to promote meal termination. We suggest that each of the factors identified by the RISE-Q represents a distinct process, and illustrate the contribution of each process to meal termination in the Satiation Framework. Within this framework the prominence of each process as a reason to stop eating likely depends on meal context in addition to individual variability. Therefore, we discuss contexts in which different processes may be salient as determinants of meal termination. Expanding the definition of satiation to include several dynamic processes as illustrated in the Satiation Framework will help to stimulate investigation and understanding of the complex nature of meal termination.

Fast Eating Is Associated with Increased BMI among High-School Students

Fast self-reported eating rate (SRER) has been associated with increased adiposity in children and adults. No studies have been conducted among high-school students, and SRER has not been validated vs. objective eating rate (OBER) in such populations. The objectives were to investigate (among high-school student populations) the association between OBER and BMI z-scores (BMIz), the validity of SRER vs. OBER, and potential differences in BMIz between SRER categories. Three studies were conducted. Study 1 included 116 Swedish students (mean ± SD age: 16.5 ± 0.8, 59% females) who were eating school lunch. Food intake and meal duration were objectively recorded, and OBER was calculated. Additionally, students provided SRER. Study 2 included students (n = 50, mean ± SD age: 16.7 ± 0.6, 58% females) from Study 1 who ate another objectively recorded school lunch. Study 3 included 1832 high-school students (mean ± SD age: 15.8 ± 0.9, 51% females) from Sweden (n = 748) and Greece (n = 1084) who provided SRER. In Study 1, students with BMIz ≥ 0 had faster OBER vs. students with BMIz < 0 (mean difference: +7.7 g/min or +27%, p = 0.012), while students with fast SRER had higher OBER vs. students with slow SRER (mean difference: +13.7 g/min or +56%, p = 0.001). However, there was “minimal” agreement between SRER and OBER categories (κ = 0.31, p < 0.001). In Study 2, OBER during lunch 1 had a “large” correlation with OBER during lunch 2 (r = 0.75, p < 0.001). In Study 3, fast SRER students had higher BMIz vs. slow SRER students (mean difference: 0.37, p < 0.001). Similar observations were found among both Swedish and Greek students. For the first time in high-school students, we confirm the association between fast eating and increased adiposity. Our validation analysis suggests that SRER could be used as a proxy for OBER in studies with large sample sizes on a group level. With smaller samples, OBER should be used instead. To assess eating rate on an individual level, OBER can be used while SRER should be avoided.

Out of the lab and into the wild: The influence of portion size on food intake in laboratory vs. real-world settings

External influences on eating behaviour, such as portion size, have been reliably shown to influence food intake in the laboratory. However, little research has examined whether laboratory settings under or overestimate the effect that external influences have on food intake compared to when studied in the real-world. In Study 1, 60 participants (mean age = 32 years) were randomized to consume a large (200 g) or small (100 g) portion of popcorn under controlled laboratory conditions and during a separate session in their home. Results showed that the effect of portion size on food intake was larger at home (d = 0.97) than in the laboratory (d = 0.56). Furthermore, participants reported feeling more relaxed eating at home compared to the laboratory. In Study 2, we examined whether comparable results were observed in a semi-naturalistic laboratory designed to resemble a home setting. 59 participants (mean age = 28 years) completed the same procedure as Study 1 in a standard and a semi-naturalistic laboratory setting. Although participants reported having higher levels of private self-awareness in the standard laboratory, the effect that portion size had on food intake did not differ between the standard laboratory (d = 0.50) and the semi-naturalistic laboratory (d = 0.49). The impact that external influences on eating, such as portion size, have on food intake in the real-world may be underestimated when studied under laboratory conditions.

Unpalatable food for thought: Let marketing research guide effective public obesity interventions

The prevalence of obesity is growing unabatedly despite the considerable efforts directed at the problem. Although abundant research has contributed to our understanding of the multifactorial causes of obesity, there is less attention to research that is relevant for guiding social marketers, public health professionals and policymakers in delivering public health interventions for countering and/or preventing the problem of obesity. This review offers six points for identifying and developing research relevant for guiding community-wide obesity interventions based on the idea that an applied marketing research perspective offers a better model for identifying effective interventions than more theoretical academic research. Specifically, the research guiding public health and social marketing interventions needs to (1) provide information on ultimate outcomes (weight, health and unintended consequences) more than intermediate outcomes (beliefs, attitudes and behaviour), (2) report on observations collected over the longer term, (3) use natural settings (even at a cost of internal validity), (4) endeavour to overcome observer-effects, (5) report effect sizes (rather than statistical significance) and (6) use moderator analyses to capture variation in how a population responds to interventions.

Virtual Reality as a Tool to Study the Influence of the Eating Environment on Eating Behavior: A Feasibility Study

In this manuscript, we describe a new approach to study the effect of the eating environment on food intake and eating behavior using virtual reality technology. Fifteen adults consumed pizza rolls in two virtual reality (VR) environments: a restaurant and a table in an empty room. The participants' food intake, eating parameters (e.g., masticatory parameters and eating rate), and their sensory evaluation of the test food was measured. The participants' sense of presence (the feeling of being in the virtual environment) and markers of arousal were also measured. There was no statistical significant difference in food intake or the sensory evaluation of the test food. In the restaurant condition, participants used fewer masticatory cycles before swallowing but there was no effect on eating rate or maximum bite force. Participants experienced a greater sense of presence when they were in the pizza restaurant scene. Moreover, their heart rate and skin temperature were higher in the restaurant condition. This study suggests that VR could be developed as a new tool to study the effect of the eating environment on food intake and eating behavior.

Using Smartphones When Eating Increases Caloric Intake in Young People: An Overview of the Literature

Recent literature highlights that the use of smartphones during meals increases the number of calories ingested in young people. Although the distraction interferes with physiological signals of hunger and satiety, a social facilitation effect has also been suggested. Cognition is a pivotal component in regulating food intake, and activities requiring high perceptual demands should be discouraged during meals.

Consumption of a smoothie or cereal-based breakfast: impact on thirst, hunger, appetite and subsequent dietary intake

Smoothies are a popular breakfast option. However, liquids may evoke weaker satiation than nutritionally comparable semi-solid and solid foods. This study examined consumption of cereal and milk (CM) or a nutritionally comparable fruit smoothie (FS) for breakfast on subsequent dietary behaviours, in a controlled laboratory setting. Twenty-five participants (age 25 ± 6 y) completed three trials, receiving either CM or FS for breakfast. Afterwards, participants remained isolated for 4 h with ad libitum access to foods/beverages. A repeat trial (CM or FS) allowed exploration of normal variability. Post-breakfast energy intake (EI) (CM = 1465(2436) vs. FS = 1787(3190) kJ, Median (IQR), p = 0.099), time to intake of next food/fluid (meal latency) (CM = 146(97) vs. FS = 180(100) min, p = 0.127), and subjective hunger, desire to eat, fullness and thirst ratings were similar between conditions (p's > 0.05). The mean coefficient of variation for EI and meal latency were 41% and 21%, respectively. Consumption of a FS does not negatively impact acute EI and meal latency.

Effects of eating with an augmented fork with vibrotactile feedback on eating rate and body weight: a randomized controlled trial

Background

Eating rate is a basic determinant of appetite regulation: people who eat more slowly feel sated earlier and eat less. A high eating rate contributes to overeating and potentially to weight gain. Previous studies showed that an augmented fork that delivers real-time feedback on eating rate is a potentially effective intervention to decrease eating rate in naturalistic settings. This study assessed the impact of using the augmented fork during a 15-week period on eating rate and body weight.

Methods

In a parallel randomized controlled trial, 141 participants with overweight (age: 49.2 ± 12.3 y; BMI: 31.5 ± 4.48 kg/m2) were randomized to intervention groups (VFC, n = 51 or VFC+, n = 44) or control group (NFC, n = 46). First, we measured bite rate and success ratio on five consecutive days with the augmented fork without feedback (T1). The intervention groups (VFC, VFC+) then used the same fork, but now received vibrotactile feedback when they ate more than one bite per 10 s. Participants in VFC+ had additional access to a web portal with visual feedback. In the control group (NFC), participants ate with the fork without either feedback. The intervention period lasted four weeks, followed by a week of measurements only (T2) and another measurement week after eight weeks (T3). Body weight was assessed at T1, T2, and T3.

Results

Participants in VFC and VFC+ had a lower bite rate (p < .01) and higher success ratio (p < .0001) than those in NFC at T2. This effect persisted at T3. In both intervention groups participants lost more weight than those in the control group at T2 (p < .02), with no rebound at T3.

Conclusions

The findings of this study indicate that an augmented fork with vibrotactile feedback is a viable tool to reduce eating rate in naturalistic settings. Further investigation may confirm that the augmented fork could support long-term weight loss strategies.

Trial registration

The research reported in this manuscript was registered on 4 November 2015 in the Netherlands Trial Register with number NL5432 (https://www.trialregister.nl/trial/5432).

Who are we testing? Self-selection bias in laboratory-based eating behaviour studies

Research conducted in controlled laboratory settings plays an important role in understanding human eating behaviour. However, participant characteristics may affect motivation to participate in laboratory eating behaviour research and result in self-selection biases. First-year psychology students (n = 207, 90.8% female, m age = 18.8, m BMI = 21.9) were led to believe that they were choosing between enrolling in one of two laboratory-based studies: an 'advertising' study, or an 'advertising and food' study; the latter specified that participants would consume food and answer questions about their eating behaviour. Participants subsequently reported demographic information and completed a series of questionnaires assessing psychological characteristics hypothesised to predict self-selection in laboratory eating studies. The majority of participants preferred to participate in a study unrelated to eating over an eating-related study (70.5%, χ² (1) = 34.90, p < .001). Participants choosing the eating-related study over the non-eating study had higher self-reported external eating tendencies and positive preoccupations with food, lower negative preoccupations with food and social appearance anxiety. Participants choosing the eating related study were also more likely to be male than female, although the number of males in the study was small (n = 19) and this finding should therefore be interpreted with caution. The present study provides some evidence that in university based samples of participants there are likely self-selection biases in laboratory-based eating behaviour studies and researchers may benefit from considering the potential influence of self-selection biases when conducting eating behaviour research.

A review of evidence supporting current strategies, challenges, and opportunities to reduce portion sizes

Although there is considerable evidence for the portion-size effect and its potential impact on health, much of this has not been successfully applied to help consumers reduce portion sizes. The objective of this review is to provide an update on the strength of evidence supporting strategies with potential to reduce portion sizes across individuals and eating contexts. Three levels of action are considered: food-level strategies (targeting commercial snack and meal portion sizes, packaging, food labels, tableware, and food sensory properties), individual-level strategies (targeting eating rate and bite size, portion norms, plate-cleaning tendencies, and cognitive processes), and population approaches (targeting the physical, social, and economic environment and health policy). Food- and individual-level strategies are associated with small to moderate effects; however, in isolation, none seem to have sufficient impact on food intake to reverse the portion-size effect and its consequences. Wider changes to the portion-size environment will be necessary to support individual- and food-level strategies leading to portion control.

Child and adult snack food intake in response to manipulated pre-packaged snack item quantity/variety and snack box size: a population-based randomized trial

OBJECTIVES

Snacks contribute to overconsumption of energy-dense foods and thence obesity. Previous studies in this area are limited by self-reported data and small samples. In a large population-based cohort of parent-child dyads, we investigated how modification of pre-packaged snack food, i.e. (a) item quantity and variety, and (b) dishware (boxed container) size affected intake.

METHODS

Design: Randomized trial nested within the cross-sectional Child Health CheckPoint of the Longitudinal Study of Australian Children, clustered by day of visit.

SAMPLE

1299 11-12 year olds, 1274 parents.

EXPOSURE

2 × 2 manipulation of snack box container size and item quantity/variety: (1) small box, few items, (2) large box, few items, (3) small box, more items, (4) large box, more items.

PROCEDURE

Participants received a snack box during a 15 min break within their 3.5 h visit; any snacks remaining were weighed.

OUTCOMES

Consumed quantity (grams) and energy intake (kilojoules).

ANALYSES

Unadjusted linear regression.

RESULTS

Children who were offered a greater quantity and variety of snack items consumed considerably more energy and a slightly higher food mass (main effect for energy intake: 349 kJ, 95% CI 282-416, standardized mean difference (effect size) 0.66; main effect for mass: 10 g, 95% CI 3-17, effect size 0.17). In contrast, manipulating box size had little effect on child consumption, and neither box size nor quantity/variety of items consistently affected adults' consumption.

CONCLUSION

In children, reducing the number and variety of snack food items available may be a more fruitful intervention than focusing on container or dishware size. Effects observed among adults were small, although we could not exclude social desirability bias in adults aware of observation.

When a portion becomes a norm: Exposure to a smaller vs. larger portion of food affects later food intake

BACKGROUND

Portion sizes in the food environment may communicate information about what constitutes a 'normal' amount of food to eat. Here we examined whether mere visual exposure to a smaller vs. larger portion size of snack food affects perceptions of how much a 'normal' sized portion is and how much people choose to eat of that food in future.

METHODS

Under the guise of a study on taste preference and personality, 104 female participants were randomly allocated to be exposed to either a smaller or larger portion size of snack food. Twenty-four hours later participants freely selected a portion of the snack food to consume and reported on their perception of what constituted a normal sized portion of the snack food.

RESULTS

Participants that were exposed to a smaller, as opposed to larger portion size subsequently believed that a normal portion of the snack food was smaller in size. Exposure to the smaller as opposed to the larger portion size also resulted in participants consuming less snack food the next day.

CONCLUSIONS

Environmental exposure to smaller, as opposed to larger portion sizes of food may change perceptions of what constitutes a normal amount of food to eat and affect the amount of food people choose to eat in future.

Parenting quality in infancy and emotional eating in adolescence: Mediation through emotion suppression and alexithymia

This study assessed the association between parenting quality at age 15 and 28 months and emotional eating (EE) at age 12 and 16 years through serial mediation by suppression of emotions and alexithymia at 12 years. The sample included 129 children and their parents. Lower parental quality in infancy was related to more suppression of emotions, which in turn was related to more difficulty identifying emotions, and in turn to higher EE in adolescence. This serial mediation model was significant for EE at 12 years, and for EE at 16 years. If future studies reveal converging findings, this knowledge points to the need for programs preventing the development of EE in adolescence through increasing the quality of parenting in infancy.

Studying human eating behaviour in the laboratory: Theoretical considerations and practical suggestions

Robinson and colleagues (2018) make important first steps in highlighting the shortcomings of laboratory studies of human eating behaviour, and providing some general suggestions to increase methodological and reporting quality. In this commentary, we present additional important theoretical considerations and practical suggestions. First, we discuss the role of situational cues in eating behaviour and highlight the implications for designing ecologically valid laboratory experiments. Next, we discuss food intake in laboratory settings in the context of the distinction between implicit and explicit measures used widely in social psychology, and provide practical recommendations to keep intake a relatively implicit measure. Finally, we recognise that designing optimal experiments requires significant resources so we present a practical procedure to recruit the smallest informative sample via Bayesian sequential hypothesis testing.

Methodological and reporting quality in laboratory studies of human eating behavior

The methodological quality and reporting practices of laboratory studies of human eating behavior determine the validity and replicability of nutrition science. The aim of this research was to examine basic methodology and reporting practices in recent representative laboratory studies of human eating behavior. We examined laboratory studies of human eating behavior (N = 140 studies) published during 2016. Basic methodology (e.g., sample size, use of participant blinding) and reporting practices (e.g., information on participant characteristics) were assessed for each study. Some information relating to participant characteristics (e.g., age, gender) and study methodology (e.g., length of washout periods in within-subjects studies) were reported in the majority of studies. However, other aspects of study reporting, including participant eligibility criteria and how sample size was determined were frequently not reported. Studies often did not appear to standardize pre-test meal appetite or attempt to blind participants to study aims. The average sample size of studies was small (between-subjects design studies in particular) and the primary statistical analyses in a number of studies (24%) were reliant on very small sample sizes that would be likely to produce unreliable results. There are basic methodology and reporting practices in the laboratory study of human eating behavior that are sub-optimal and this is likely to be affecting the validity and replicability of research. Recommendations to address these issues are discussed.

The bogus taste test: Validity as a measure of laboratory food intake

Because overconsumption of food contributes to ill health, understanding what affects how much people eat is of importance. The ‘bogus’ taste test is a measure widely used in eating behaviour research to identify factors that may have a causal effect on food intake. However, there has been no examination of the validity of the bogus taste test as a measure of food intake. We conducted a participant level analysis of 31 published laboratory studies that used the taste test to measure food intake. We assessed whether the taste test was sensitive to experimental manipulations hypothesized to increase or decrease food intake. We examined construct validity by testing whether participant sex, hunger and liking of taste test food were associated with the amount of food consumed in the taste test. In addition, we also examined whether BMI (body mass index), trait measures of dietary restraint and over-eating in response to palatable food cues were associated with food consumption. Results indicated that the taste test was sensitive to experimental manipulations hypothesized to increase or decrease food intake. Factors that were reliably associated with increased consumption during the taste test were being male, have a higher baseline hunger, liking of the taste test food and a greater tendency to overeat in response to palatable food cues, whereas trait dietary restraint and BMI were not. These results indicate that the bogus taste test is likely to be a valid measure of food intake and can be used to identify factors that have a causal effect on food intake.

Higher BMI is associated with stronger effects of social cues on everyday snacking behaviour

Discretionary food choices (snacks) contribute up to a third of the daily energy intake and potentially contribute to energy imbalance and weight gain. Individual snack intake behaviour is guided by internal and external cues, with social cues (seeing others eat, being alone) consistently showing large effects. A wide body of (mainly laboratory-based) research suggests marked differences in people's response to eating cues based on BMI. Here, we show that these BMI differences in cue responsiveness also pertain to everyday snacking behaviour. In two combined ecological momentary assessment studies, 122 participants with BMIs ranging from 18.34 to 45.71 kg/m² logged their everyday snacking behaviour in real-time over two weeks along with the presence or absence of social cues. Random-effects modelling showed that people with higher BMI were more likely to consume high-energy snacks when alone, and were more likely to consume low-energy snacks in the presence of others eating. This suggests BMI differences in cue responsiveness that are in line with impression management theory and underlines the importance of social cues for snacking behaviour and provides avenues for both theory and intervention development.

Stress-induced eating in women with binge-eating disorder and obesity

The purpose of the current study was to investigate stress-induced eating in women with binge-eating disorder (BED) and obesity. Three groups of women [obese with BED (n=9); obese non-BED (n=11); and normal weight (NW) non-BED (n=12)], rated their levels of hunger and psychological distress before and after completing the Trier Social Stress Test, followed by food anticipation and then consumption of their preferred snack food. We differentiated between the motivational and hedonic components of eating by measuring the amount of food participants poured into a serving bowl compared to the amount consumed. Stress did not affect poured and consumed calories differently between groups. Across all subjects, calories poured and consumed were positively correlated with post-stress hunger, but calories poured was positively correlated with post-stress anxiety and negative affect. These results indicate that stress-related psychological factors may be more strongly associated with the motivational drive to eat (i.e. amount poured) rather than the hedonic aspects of eating (i.e. amount consumed) for women in general. Exploratory correlation analyses per subgroup suggest that post-stress hunger was positively associated with calories poured and consumed in both non-BED groups. In the obese BED group, calories consumed was negatively associated with dietary restraint and, although not significantly, positively associated with stress-induced changes in anxiety.These findings suggest that stress-induced snacking in obese BED women may be influenced by psychological factors more so than homeostatic hunger mechanisms. After controlling for dietary restraint and negative affect, the NW non-BED women ate a greater percentage of the food they poured than both obese groups, suggesting that obesity may be associated with a heightened motivational drive to eat coupled with a reduction in hedonic pleasure from eating post-stress. Further studies that incorporate novel approaches to measuring the motivational versus hedonic aspects of stress-induced eating may expose nuanced eating behaviors that differentiate BED and obesity. If confirmed, our findings would support prevention and treatment strategies that target subsets of women based on obesity and BED status.

The effect of heightened awareness of observation on consumption of a multi-item laboratory test meal in females

Human eating behaviour is often studied in the laboratory, but whether the extent to which a participant believes that their food intake is being measured influences consumption of different meal items is unclear. Our main objective was to examine whether heightened awareness of observation of food intake affects consumption of different food items during a lunchtime meal. One hundred and fourteen female participants were randomly assigned to an experimental condition designed to heighten participant awareness of observation or a condition in which awareness of observation was lower, before consuming an ad libitum multi-item lunchtime meal in a single session study. Under conditions of heightened awareness, participants tended to eat less of an energy dense snack food (cookies) in comparison to the less aware condition. Consumption of other meal items and total energy intake were similar in the heightened awareness vs. less aware condition. Exploratory secondary analyses suggested that the effect heightened awareness had on reduced cookie consumption was dependent on weight status, as well as trait measures of dietary restraint and disinhibition, whereby only participants with overweight/obesity, high disinhibition or low restraint reduced their cookie consumption. Heightened awareness of observation may cause females to reduce their consumption of an energy dense snack food during a test meal in the laboratory and this effect may be moderated by participant individual differences.

•

We examined the effect of heightened awareness of observation on food intake.

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This caused female participants to eat less of an energy dense snack food.

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This effect was moderated by weight status and trait eating behaviour measures.

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Heightened awareness of observation had little effect on intake of other foods.

Advertising as a cue to consume: a systematic review and meta-analysis of the effects of acute exposure to unhealthy food and nonalcoholic beverage advertising on intake in children and adults

BACKGROUND

Several studies have assessed the effects of food and nonalcoholic beverage (hereafter collectively referred to as food) advertising on food consumption, but the results of these studies have been mixed. This lack of clarity may be impeding policy action.

OBJECTIVE

We examined the evidence for a relation between acute exposure to experimental unhealthy food advertising and food consumption.

DESIGN

The study was a systematic review and meta-analysis of published studies in which advertising exposure (television or Internet) was experimentally manipulated, and food intake was measured. Five electronic databases were searched for relevant publications (SCOPUS, PsycINFO, MEDLINE, Emerald Insight, and JSTOR). An inverse variance meta-analysis was used whereby the standardized mean difference (SMD) in food intake was calculated between unhealthy food advertising and control conditions.

RESULTS

Twenty-two articles were eligible for inclusion. Data were available for 18 articles to be included in the meta-analysis (which provided 20 comparisons). With all available data included, the analysis indicated a small-to-moderate effect size for advertising on food consumption with participants eating more after exposure to food advertising than after control conditions (SMD: 0.37; 95% CI: 0.09; 0.65; I(2) = 98%). Subgroup analyses showed that the experiments with adult participants provided no evidence of an effect of advertising on intake (SMD: 0.00; P = 1.00; 95% CI: -0.08, 0.08; I(2) = 8%), but a significant effect of moderate size was shown for children, whereby food advertising exposure was associated with greater food intake (SMD: 0.56; P = 0.003; 95% CI: 0.18, 0.94; I(2) = 98%).

CONCLUSIONS

Evidence to date shows that acute exposure to food advertising increases food intake in children but not in adults. These data support public health policy action that seeks to reduce children's exposure to unhealthy food advertising.

The ad-libitum alcohol 'taste test': secondary analyses of potential confounds and construct validity

RATIONALE

Motivation to drink alcohol can be measured in the laboratory using an ad-libitum 'taste test', in which participants rate the taste of alcoholic drinks whilst their intake is covertly monitored. Little is known about the construct validity of this paradigm.

OBJECTIVE

The objective of this study was to investigate variables that may compromise the validity of this paradigm and its construct validity.

METHODS

We re-analysed data from 12 studies from our laboratory that incorporated an ad-libitum taste test. We considered time of day and participants' awareness of the purpose of the taste test as potential confounding variables. We examined whether gender, typical alcohol consumption, subjective craving, scores on the Alcohol Use Disorders Identification Test and perceived pleasantness of the drinks predicted ad-libitum consumption (construct validity).

RESULTS

We included 762 participants (462 female). Participant awareness and time of day were not related to ad-libitum alcohol consumption. Males drank significantly more alcohol than females (p < 0.001), and individual differences in typical alcohol consumption (p = 0.04), craving (p < 0.001) and perceived pleasantness of the drinks (p = 0.04) were all significant predictors of ad-libitum consumption.

CONCLUSIONS

We found little evidence that time of day or participant awareness influenced alcohol consumption. The construct validity of the taste test was supported by relationships between ad-libitum consumption and typical alcohol consumption, craving and pleasantness ratings of the drinks. The ad-libitum taste test is a valid method for the assessment of alcohol intake in the laboratory.

The Possible Antecedents and Consequences of Matching of Food Intake: Examining the Role of Trait Self-Esteem and Interpersonal Closeness

Although there is evidence that people tend to match their intake to that of others, less is known about the motives underlying this effect. The current study, therefore, examined the relationship between self-esteem, a specific factor that has been related to the likelihood of social matching. Further, we examined the effects of food matching on interpersonal closeness among eating companions. The sample included 89 female dyads. All dyads had free access to palatable snack food during a 15 min interaction. For each dyad the matching score was calculated, as well as both individual's trait self-esteem scores and interpersonal closeness with their eating partner. The overall degree of matching within dyads was high, replicating the findings of previous research. No relationship, however, was found between trait self-esteem and the degree of matching. Furthermore, there was no effect of matching on perceived interpersonal closeness with or liking of the other person. These results suggest that self-esteem might not be a robust predictor of matching and that matching of food intake may not result in increased perceived interpersonal closeness or liking among eating partners.

Eating under observation: a systematic review and meta-analysis of the effect that heightened awareness of observation has on laboratory measured energy intake

BACKGROUND

Laboratory paradigms are commonly used to study human energy intake. However, the extent to which participants believe their eating behavior is being measured may affect energy intake and is a methodologic factor that has received little consideration.

OBJECTIVE

Our main objective was to examine available evidence for the effect that heightened awareness of observation has on energy intake in a laboratory setting.

DESIGN

We systematically reviewed laboratory studies that allowed for experimental examination of the effect that heightened awareness of observation has on energy intake. From these experimental studies we combined effect estimates using inverse variance meta-analysis, calculating the standardized mean difference (SMD) in energy intake between heightened-awareness and control conditions and qualitatively synthesized potential moderators of this effect.

RESULTS

Nine studies, providing 22 comparisons, were eligible for inclusion. These studies largely sampled young women and examined the energy intake of energy-dense snack foods. Evidence indicated that heightened awareness of observation was associated with reduced energy intake when compared with the control condition (random-effects SMD: 0.45; 95% CI: 0.25, 0.66; P < 0.0001). We found little evidence that the type of experimental manipulation used to heighten awareness moderated the overall effect.

CONCLUSIONS

The available evidence to date suggests that heightened awareness of observation reduces energy intake in a laboratory setting. These findings suggest that laboratory studies should attempt to minimize the degree to which participants are aware that their eating behavior is being measured.

Effects of awareness that food intake is being measured by a universal eating monitor on the consumption of a pasta lunch and a cookie snack in healthy female volunteers

To date, there have been no studies that have explicitly examined the effect of awareness on the consumption of food from a Universal Eating Monitor (UEM - hidden balance interfaced to a computer which covertly records eating behaviour). We tested whether awareness of a UEM affected consumption of a pasta lunch and a cookie snack. 39 female participants were randomly assigned to either an aware or unaware condition. After being informed of the presence of the UEM (aware) or not being told about its presence (unaware), participants consumed ad-libitum a pasta lunch from the UEM followed by a cookie snack. Awareness of the UEM did not significantly affect the amount of pasta or cookies eaten. However, awareness significantly reduced the rate of cookie consumption. These results suggest that awareness of being monitored by the UEM has no effect on the consumption of a pasta meal, but does influence the consumption of a cookie snack in the absence of hunger. Hence, energy dense snack foods consumed after a meal may be more susceptible to awareness of monitoring than staple food items.

Awareness of social influence on food intake. An analysis of two experimental studies

There is consistent evidence that the amount of food we consume can be influenced by the eating behaviour of other people. Some previous experimental studies reported that consumers are unaware of this influence on their behaviour. The present research tested whether people may be more aware of social influence on their eating than previously assumed. In two studies, participants (total n = 160) were exposed to information about the amount of snack food other people had been eating shortly before being served the same snack food and eating as much as they liked. After this, participants responded to questions regarding whether they thought their food intake had been socially influenced, and reported the reasons why they believed they had or had not been influenced. Of the 160 participants, 34% reported that they had been influenced, 10% were unsure and 56% reported they had not been influenced. Crucially, participants' reports of social influence appeared to be accurate; the food intake of participants reporting social influence was significantly affected by the amount of food other people had been eating, whereas the food intake of participants denying social influence was unaffected. Individuals may be more aware of the effect that social influence has on their eating behaviour than previously assumed. Further work is needed to identify the factors which determine whether people are susceptible to social influence on eating behaviour.