Effects of food stimuli on event-related potentials of restrained eating subgroups during task switching

Executive functions are thought to affect problematic eating behaviors in restrained eaters. While neurophysiological features of inhibitory control among restrained eaters in particular have been extensively investigated, considerably less is known about its influence on cognitive flexibility. The present study investigated the behavioral and neural correlates of food-related cognitive flexibility with event-related potentials (ERPs) associated in a task-switching paradigm among successful restrained eaters (SREs, n = 30) and unsuccessful restrained eaters (UREs, n = 32). Behavioral results revealed smaller switch reaction times among SREs than among UREs in both food-stimuli and neutral-stimuli tasks. ERP analyses indicated that neutral-switch trials, especially in UREs, displayed larger N2 amplitudes. In addition, SREs displayed larger P3 amplitudes in frontal, frontal-central, and central than UREs. P3 amplitude increased significantly during food-stimuli tasks compared to that during neutral-stimuli tasks. These results indicate that SREs possess better efficiency in enhanced cognitive transformation during the processing of target monitoring and conflict resolution. This is the first study to provide evidence for differences between SREs and UREs during task switching using ERP measures and reliance on different food-related processing strategies among SREs compared to UREs.

Lack of conflict during food choice is associated with the failure of restrained eating

Restrained eaters tend to sustain a restriction in caloric intake to lose or maintain body weight; however, only a few restrained eaters can achieve the goal of restricting their caloric intake to lose or maintain body weight. Those who are effective restrained eaters habitually adhere to their intentions to avoid eating certain palatable foods, whereas those who are ineffective restrained eaters are generally unable to translate their intentions into behavior. To restrain eating regardless of temptation, an individual must first identify potential conflicts between achieving restrained eating and temptation to eat. Regarding food selections, the association between a lack of conflict between temptation, eating enjoyment, and weight loss or maintenance goals and the failure of restriction of caloric intake remains unknown. The present study used an eye-tracking technique to assess the degree of conflict experienced by effective and ineffective restrained eaters during food choice. Participants were required to choose between pairs of high- and low-calorie foods. The results showed that choosing the low-calorie food was associated with the experience of more conflict, measured by longer response times and more gaze switches, than choosing the high-calorie food. Ineffective restrained eaters experienced less conflict, exhibiting shorter response times and fewer gaze switches, than did effective restrained eaters, which suggests that a failure to restrain eating might be associated with a lack of experience of conflict.

Cognitive restriction accentuates the increased energy intake response to a 10-month multidisciplinary weight loss program in adolescents with obesity

BACKGROUND

Multidisciplinary interventions have shown some merits in weight reduction strategies in youth, however, their impact on subsequent daily energy intake remains largely unknown. The aim of the present study was to evaluate the nutritional responses to a 10-month multidisciplinary intervention among adolescents with obesity, in relation to their eating behavior characteristics.

METHODS

Thirty-five adolescents (mean age: 13.4 ± 1.2 years) with obesity took part in a 10-month residential multidisciplinary weight loss program. Anthropometric measurements, body composition (dual-energy X-ray absorptiometry), 24-h ad libitum energy intake (weighted), eating behaviors (Dutch Eating Behavior Questionnaire) and appetite sensations (Visual Analogue Scales) were assessed on three occasions: at their arrival in the institution (T0), after 5 months (T1), and at the end of the 10-month program (T2).

RESULTS

The mean weight loss reached 11% of the adolescents' initial body weight, with an important inter-individual variability (-25% to +3% of their initial body weight). Results revealed sex differences change, with boys showing a higher decrease in fat mass percent and increase in fat-free mass compared with girls. Weight loss was accompanied by a significant decrease in emotional (-8.3%, p < 0.05) and external (-14.8%, p < 0.001) eating scores and a significant increase in 24-h ad libitum energy intake (+246 kcal, p < 0.001). The observed subsequent increased 24-h ad libitum energy intake at T2 compared to T0 was significantly higher in cognitively restrained eaters (+492 kcal) compared to unrestrained eaters (+115 kcal, p = 0,015). Dietary restraint score at baseline was inversely correlated with the percentage of weight loss (r = -0.44, p = 0.010).

CONCLUSION

A 10-month multidisciplinary weight loss intervention induced an increase in 24-h ad libitum energy intake compared to baseline, especially in cognitively restrained eaters. Moreover, initially cognitively restrained eaters tended to lose less body weight compared to unrestrained ones. These findings suggest that cognitive restriction may be a useful eating behavior characteristic to consider as a screening tool for identifying adverse responders to weight loss interventions in youth.

Restrained Eating and Food Cues: Recent Findings and Conclusions

PURPOSE OF REVIEW

The purposes of the present review are to organize the recent literature on the effects of food cues on restrained and unrestrained eaters and to determine current directions in such work.

RECENT FINDINGS

Research over the last several years involves both replicating the work showing that restrained eaters respond to attractive food cues by eating more but unrestrained eaters show less responsiveness and extending this work to examine the mechanisms that might underlie this differential responsiveness. Labeling a food as healthy encourages more eating by restrained eaters, while diet-priming cues seem to curtail their consumption even in the face of attractive food cues. Work on cognitive responses indicates that restrained (but not unrestrained) eaters have both attention and memory biases toward food cues. Restrained eaters attend more strongly to food- and diet-related cues than do unrestrained eaters, as evidenced in both their eating behavior and their attention and memory responses to such cues. These effects interact with expectations and manner of presentation of such cues. What remains to be understood is the meaning and mechanism of the attention bias toward food cues in restrained eaters and the implications of such bias for overeating and overweight more broadly speaking.

What's that you're eating? Social comparison and eating behavior

People seem to have a basic drive to assess the correctness of their opinions, abilities, and emotions. Without absolute indicators of these qualities, people rely on a comparison of themselves with others. Social comparison theory can be applied to eating behavior. For example, restrained eaters presented with a standard slice of pizza ate more of a subsequent food if they thought that they had gotten a bigger slice of pizza than others (i.e., had broken their diets), whereas unrestrained eaters ate less. Social influences on eating such as modeling and impression formation also rely on comparison of one's own eating to others. Comparing one's food to others' meals generally influences eating, affect, and satisfaction.

Tempting foods and the affordability axiom: Food cues change beliefs about the costs of healthy eating

Many consumers report that healthy eating is more expensive than unhealthy eating (the affordability axiom). We hypothesize that endorsement of this belief may be driven by the motivation to eat unhealthy foods. We tested this hypothesis in three studies. Study 1 revealed that the affordability axiom is associated with poorer eating habits and higher Body Mass Index (BMI). Study 2 found that the presence of a tasty food cue in the environment increased endorsement of affordability axiom. Study 3 found that these effects were moderated by one's food intake goals. Food cues led non-dieters to increase endorsement of the affordability axiom, but had the opposite effect among those seeking to restrict their calorie intake. The affordability axiom might persist as a means of validating unhealthy food choices.

High satiety expectations of a first course promote selection of less energy in a main course picture task

One of the factors determining meal size is the expectation one has about satiating properties of foods. Foods eliciting low satiety expectations are often chosen in larger portions. We investigated whether satiety expectations of one food lead to a different portion size selection of other foods, using an online picture task. One hundred and twenty-six subjects (64 unrestrained, 62 restrained) participated in three conditions (within-subject). In two conditions subjects were asked to imagine they consumed soup as a first course. They were shown pictures of soups differing in terms of visual attributes, e.g. colour intensity, ingredients variety, etc. that conveyed a high or low expected satiety. In the control condition, no picture was shown. After viewing either a soup picture or no picture, subjects chose an ideal menu and portion size out of several other foods (meat, side dishes and vegetables) via an online choice task, specifically developed for this experiment. The energy (kcal) and weight (grams) selected for the main course was measured. More energy was chosen in the low satiety compared with the high satiety soup picture condition, but this effect was only significant for restrained eaters. This study shows that satiety expectations of a first course 'carry over' to the rest of the menu in people who carefully watch their diet, i.e. restrained eaters make satiety estimations for an entire menu. Our online choice task was able to capture these estimations in an implicit manner.

"She got more than me". Social comparison and the social context of eating

Eating is a social activity for most people. Other people influence what and how much an individual chooses and eats. Such social influence on eating has long been recognized and studied, but we contend here that one important social influence factor, social comparison, has been largely overlooked by researchers. We review the literature on comparing oneself to others on eating and weight-related dimensions, which appears to have an effect not only on eating per se, but also on self-image, body dissatisfaction, and emotions. Social comparison processes may well underlie many of the social influence findings discussed in this special issue.

Focusing on media body ideal images triggers food intake among restrained eaters: a test of restraint theory and the elaboration likelihood model

Although research consistently shows that images of thin women in the media (media body ideals) affect women negatively (e.g., increased weight dissatisfaction and food intake), this effect is less clear among restrained eaters. The majority of experiments demonstrate that restrained eaters - identified with the Restraint Scale - consume more food than do other participants after viewing media body ideal images; whereas a minority of experiments suggest that such images trigger restrained eaters' dietary restraint. Weight satisfaction and mood results are just as variable. One reason for these inconsistent results might be that different methods of image exposure (e.g., slideshow vs. film) afford varying levels of attention. Therefore, we manipulated attention levels and measured participants' weight satisfaction and food intake. We based our hypotheses on the elaboration likelihood model and on restraint theory. We hypothesised that advertent (i.e., processing the images via central routes of persuasion) and inadvertent (i.e., processing the images via peripheral routes of persuasion) exposure would trigger differing degrees of weight dissatisfaction and dietary disinhibition among restrained eaters (cf. restraint theory). Participants (N = 174) were assigned to one of four conditions: advertent or inadvertent exposure to media or control images. The dependent variables were measured in a supposedly unrelated study. Although restrained eaters' weight satisfaction was not significantly affected by either media exposure condition, advertent (but not inadvertent) media exposure triggered restrained eaters' eating. These results suggest that teaching restrained eaters how to pay less attention to media body ideal images might be an effective strategy in media-literary interventions.

Positive fantasies or negative contrasts: the effect of media body ideals on restrained eaters' mood, weight satisfaction, and food intake

Although viewing media body ideals promotes body dissatisfaction and problematic eating among women (e.g., extreme restraint/overeating), some argue that women only report such negative effects because they think that they are meant to (i.e., demand characteristics). Because restrained eaters are trying to lose weight, they might be vulnerable to such media exposure. However, because of demand characteristics, evidence is mixed. Therefore, we minimized demand characteristics and explored whether media body ideals would trigger restrained eaters to report negative (negative mood, weight dissatisfaction) or positive (positive mood, weight satisfaction) effects. We also hypothesized that this change (negative or positive) would encourage food intake. Restrained and unrestrained eaters (n=107) memorized media or control images. Restrained eaters exposed to media images reported decreased weight satisfaction and increased negative mood, but their food intake was not significantly affected. Perhaps paying advertent attention to the images caused goal-related negative affect, which triggered restraint.