Social facilitation of energy intake in adult women is sustained over three days in a crossover laboratory experiment and is not compensated for under free-living conditions.

People eat more when they eat a meal with familiar others than they do when eating alone. However, it is unknown whether eating socially impacts intake over the longer-term. The aim of Study 1 was to examine whether socially facilitated intake is sustained across all meals and across three consecutive days. The aim of Study 2 was to examine whether increased intake during a social meal taken in the laboratory is compensated for under free-living conditions. In Study 1, adult women (n = 26) ate all their meals across three days either with a friend or alone in a counterbalanced cross-over design. In Study 2 adult women (n = 63) consumed a meal in the laboratory either alone or with two friends and then recorded everything they ate and drank for the next three days using electronic food diary software. In Study 1 intake across 3 days was significantly greater in the Social (M = 7310 kcal, SD = 1114) than in the Alone condition (M = 6770 kcal, SD = 974) (F(1,423) = 16.10, p < .001, d = 0.51). In Study 2 participants consumed significantly more in the laboratory when eating with their friends (M = 1209 kcal, SD = 340) than when eating alone (M = 962 kcal, SD = 301) (F(1,63) = 13.28, p = .001, d = 0.77). Analysis of food diary data plus laboratory intake showed that intake remained significantly greater in the Social (M = 6396 kcal, SD = 1470) than in the Alone condition after 4 days (M = 5776 kcal, SD = 1182) (F(1,59) = 5.59, p = .021, d = 0.05). These results show that social facilitation of eating is sustained over three days and suggest that people fail to compensate for the social facilitation of eating.

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

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

People serve themselves larger portions before a social meal.

One of the most powerful influences on food intake yet identified is the presence of familiar others at an eating occasion: people eat much more when they eat with friends/family than when they eat alone. But why this is the case is unclear. Across two studies (Study 1: N = 98; Study 2: N = 120), we found that the mere anticipation of social interaction is all that is needed to promote the selection of larger meals, and that this occurs even when a person is alone when they make their decision. Adult women served themselves larger portions when they knew they were going to eat socially versus when they knew they were going to eat alone. These data suggest that how other people influence our food intake reaches beyond the specific eating context to affect pre-meal portion size decisions, suggesting that a fundamental shift is required in our thinking about social influences on eating.

Obesity Stigma: Is the 'Food Addiction' Label Feeding the Problem?

Obesity is often attributed to an addiction to high-calorie foods. However, the effect of "food addiction" explanations on weight-related stigma remains unclear. In two online studies, participants (n = 439, n = 523, respectively, recruited from separate samples) read a vignette about a target female who was described as 'very overweight'. Participants were randomly allocated to one of three conditions which differed in the information provided in the vignette: (1) in the "medical condition", the target had been diagnosed with food addiction by her doctor; (2) in the "self-diagnosed condition", the target believed herself to be a food addict; (3) in the control condition, there was no reference to food addiction. Participants then completed questionnaires measuring target-specific stigma (i.e., stigma towards the female described in the vignette), general stigma towards obesity (both studies), addiction-like eating behavior and causal beliefs about addiction (Study 2 only). In Study 1, participants in the medical and self-diagnosed food addiction conditions demonstrated greater target-specific stigma relative to the control condition. In Study 2, participants in the medical condition had greater target-specific stigma than the control condition but only those with low levels of addiction-like eating behavior. There was no effect of condition on general weight-based stigma in either study. These findings suggest that the food addiction label may increase stigmatizing attitudes towards a person with obesity, particularly within individuals with low levels of addiction-like eating behavior.

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

BACKGROUND: Research suggests that people tend to eat more when eating with other people, compared with when they eat alone, and this is known as the social facilitation of eating. However, little is known about when and why this phenomenon occurs. OBJECTIVES: This review aimed to quantify the evidence for social facilitation of eating and identify moderating factors and underlying mechanisms. METHODS: We systematically reviewed studies that used experimental and nonexperimental approaches to examine food intake/food choice as a function of the number of co-eaters. The following databases were searched during April 2019: PsychInfo, Embase, Medline, and Social Sciences Citation Index. Studies that used naturalistic techniques were narratively synthesized, and meta-analyses were conducted to synthesize results from experimental studies. RESULTS: We reviewed 42 studies. We found strong evidence that people select and eat more when eating with friends, compared with when they eat alone [Z = 5.32; P < 0.001; standardized mean difference (SMD) = 0.76; 95% CI: 0.48, 1.03]. The meta-analysis revealed no evidence for social facilitation across studies that had examined food intake when participants ate alone or with strangers/acquaintances (Z = 1.32; P = 0.19; SMD = 0.21, 95% CI: -0.10, 0.51). There was some evidence that the social facilitation of eating is moderated by gender, weight status, and food type. However, this evidence was limited by a lack of experimental research examining the moderating effect of these factors on the social facilitation of eating among friends. In 2 studies, there was evidence that the effect of the social context on eating may be partly mediated by longer meal durations and the perceived appropriateness of eating. CONCLUSIONS: Findings suggest that eating with others increases food intake relative to eating alone, and this is moderated by the familiarity of co-eaters. The review identifies potential mechanisms for the social facilitation of eating and highlights the need for further research to establish mediating factors. Finally, we propose a new theoretical framework in which we suggest that the social facilitation of eating has evolved as an efficient evolutionary adaptation.

Guilty pleasures: The effect of perceived overeating on food addiction attributions and snack choice.

Despite being widely debated throughout the scientific community, the concept of food addiction remains a popular explanation for overeating and obesity amongst the lay public. Overeating is often accompanied by feelings of guilt and dietary concern, and this may lead people to attribute their eating to an addiction in order to minimise personal responsibility. Research also indicates that food addiction attributions and dietary concern may lead people to limit their exposure to tempting foods. To test these ideas, we examined the effect of perceived overeating on food addiction attributions and snack choice. Subjective ratings of guilt and dietary concern were indirectly manipulated by leading female participants (N=90) to believe they had eaten more than (overeating condition), less than (undereating condition), or roughly the same (control condition) amount of palatable foods in relation to their own estimated consumption and to previous participants. Participants then rated the relative importance of a list of explanations for their eating (including "the foods were really addictive") and selected a snack to take home with them. Ratings of guilt and dietary concern were highest in the overeating condition, and lowest in the undereating condition, indicating that the manipulation had been successful. However, findings revealed no effect of condition on food addiction attributions. As predicted, participants in the overeating condition selected less tempting snacks than in the undereating condition. However, this effect was not mediated by guilt/dietary concern. There was also no association between food-addiction attributions and snack choice. These findings suggest that perceived overeating affects snack choice but not food addiction attributions. Future research should investigate whether food addiction attributions may be driven by feelings of guilt and dietary concern following longer-term disinhibited eating patterns.

Food Addiction Beliefs Amongst the Lay Public: What Are the Consequences for Eating Behaviour?

PURPOSE OF REVIEW: The current paper reviews recent research on perceptions of food addiction in the lay public. It also examines the potential consequences of such beliefs for eating behaviour. RECENT FINDINGS: Surveys suggest that, within community samples, the majority of individuals believe that certain foods are addictive, and that food addiction causes obesity. Further, many people believe themselves to be 'food addicts', and these individuals demonstrate increased patterns of aberrant eating. However, there is also initial experimental evidence to suggest that believing oneself to be a food addict leads to short-term food restriction. SUMMARY: To reconcile these findings, a self-perpetuating relationship between food addiction beliefs and aberrant eating is proposed. Specifically, in the short term, food addiction beliefs may encourage individuals to avoid certain foods. However, attempts at restriction may eventually lead to increased cravings and disinhibition, thus reinforcing perceptions of oneself as a food addict. These possibilities merit scrutiny in future research.

Exploring food reward and calorie intake in self-perceived food addicts.

Previous research indicates that many people perceive themselves to be addicted to food. These 'self-perceived food addicts' may demonstrate aberrant eating patterns which put them at greater risk of overeating. However this is yet to be empirically investigated. The current study investigated whether self-perceived food addicts would exhibit higher food reward and calorie intake in a laboratory context relative to self-perceived non-addicts. A secondary aim was to investigate whether self-perceived food addicts would demonstrate increased food liking and/or increased hunger ratings. Finally, we explored whether self-perceived food addicts demonstrate patterns of aberrant eating, beyond that predicted by measures of trait dietary disinhibition and restraint. Female participants (self-perceived food addicts n = 31, non-addicts n = 29) completed measures of hunger, food reward (desire-to-eat, willingness-to-pay ratings, and an operant response task) and liking for high- and low-fat foods. Participants completed all measures when they were hungry, and again when they were satiated after consuming a fixed-lunch meal. Finally, participants were provided with ad-libitum access to high-and low-fat foods. Results indicated that self-perceived food addicts consumed more calories from high-fat food compared to non-addicts, despite the absence of any between-group differences in hunger or overall liking ratings. Self-perceived food addicts also displayed higher desire-to-eat ratings across foods compared to non-addicts, but groups did not differ on other measures of food reward. However, the differences in calorie intake and desire-to-eat between self-perceived food addicts and non-addicts were no longer significant after controlling for dietary disinhibition and restraint. These findings suggest that self-perceived food addicts experience food as more rewarding and have a tendency to overeat. However, this may be attributable to increased dietary disinhibition and decreased restraint rather than reflecting a unique pattern of aberrant eating behaviour.

Believing in food addiction: Helpful or counterproductive for eating behavior?

OBJECTIVE: Obesity is often attributed to an addiction to food, and many people believe themselves to be "food addicts." However, little is known about how such beliefs may affect dietary control and weight management. The current research examined the impact of experimentally manipulating participants' personal food addiction beliefs on eating behavior. METHODS: In two studies, female participants (study 1: N = 64; study 2: N = 90) completed food-related computerized tasks and were given bogus feedback on their performance which indicated that they had high, low, or average food addiction tendencies. Food intake was then assessed in an ad libitum taste test. Dietary concern and time taken to complete the taste test were recorded in study 2. RESULTS: In study 1, participants in the high-addiction condition consumed fewer calories than those in the low-addiction condition, F(1,60) = 7.61, P = 0.008, ηp (2) = 0.11. Study 2 replicated and extended this finding, showing that the effect of the high-addiction condition on food intake was mediated by increased dietary concern, which reduced the amount of time participants willingly spent exposed to the foods during the taste test, b = -0.06 (0.03), 95% confidence interval = -0.13 to -0.01. CONCLUSIONS: Believing oneself to be a food addict is associated with short-term dietary restriction. The longer-term effects on weight management now warrant attention.

Eating to live or living to eat? Exploring the causal attributions of self-perceived food addiction.

Previous studies indicate that many people perceive themselves to be addicted to food. However, little is known about how the concept of 'food addiction' is defined amongst members of the lay public. The current study examined beliefs about the cognitive and behavioural manifestations of food addiction. Participants (N = 210) completed an internet-delivered questionnaire in which they indicated whether or not they perceived themselves to be a food addict and provided a brief explanation for their response. Over a quarter of participants (28%) perceived themselves to be food addicts and self-diagnosis was predicted by increased BMI and younger age, but not by gender. Thematic analysis was conducted to explore the causal attributions provided by self-perceived food addicts and non-addicts. Six characteristics were identified: 1) Reward-driven eating (i.e. eating for psychological rather than physiological reasons), 2) A functional or psychological preoccupation with food, 3) A perceived lack of self-control around food, 4) Frequent food cravings, 5) Increased weight or an unhealthy diet, and 6) A problem with a specific type of food. The emergent themes, and their frequency, did not differ between self-perceived food addicts and non-addicts. However, self-perceived food addicts and non-addicts reported divergent cognitions, behaviours and attitudes within each common theme. This study is the first to provide qualitative insight into beliefs about food addiction in both self-perceived food addicts and non-addicts. The findings appear to reflect a view of food addiction that is identifiable through several core behaviours.

"Food addiction is real". The effects of exposure to this message on self-diagnosed food addiction and eating behaviour.

Food addiction is widely discussed in popular media in many Westernised societies. However, a potential concern is that endorsement of the food addiction model may cause people to perceive a lack of personal control over eating which could promote unhealthy dietary behaviours. To address this possibility, the current study investigated whether exposure to food addiction messages would, firstly, increase the number of participants who self-diagnosed as food addicts and, secondly, increase intake of indulgent foods. In a between-subjects design, participants (N = 60) read an article which either claimed that food addiction is real ("Real" condition) or that food addiction is a myth ("Myth" condition). Intake of indulgent and non-indulgent foods was then assessed in a disguised taste test and participants also completed a measure of self-diagnosed food addiction. A significantly higher proportion of participants in the Real condition self-diagnosed as food addicts relative to participants in the Myth condition (57% and 27% of participants, respectively; p = .018). Variability in intake, but not mean intake, of indulgent food was higher in the Real condition than in the Myth condition. These findings suggest that endorsement of the concept of food addiction may encourage people to self-diagnose as food addicts and thus explain their eating behaviour in terms of addiction (an external attribution). The extent to which self-diagnosis of food addiction influences actual food intake and how this might vary with individual differences and eating context remains to be determined.