A problematic counter-regulation experiment: implications for the link between dietary restraint and overeating

Disconnect between sympathetically-induced hunger suppression and consumption among highly restrained eaters following stress

Despite emphasis on findings suggesting restrained eaters increase food consumption under stress, unrestrained eaters' reduction in intake is more robust. Early proposals asserted unrestrained eaters significantly reduced intake after certain threats due to the hunger-inhibiting effects of autonomic influences, presuming unrestrained eaters are more responsive to these effects and restrained eaters rely less on physiological cues for eating. However, scant empirical evidence has substantiated these claims. This study examined whether a sequence exists whereby stress elicits autonomic activation, autonomic activation impacts hunger, and hunger then impacts eating, with dietary restraint altering the hunger-intake link. It was hypothesized that sympathetic nervous system activation would be greatest when ongoing safety from stress was uncertain, sympathetic activation would be linked to reduced hunger, and lower hunger would be associated with attenuated intake. Restraint, conceptualized via Hagan et al.'s (2017) latent restraint factors, was hypothesized to reduce the association between hunger and intake. Female participants (n = 147) were randomized to a stress + certain safety, stress + uncertain safety, or control condition. Sympathetic nervous system activity was recorded prior to a bogus taste test, which quantified ad libitum consumption of highly-palatable snack foods post-stress. Only the stress + uncertain safety condition exhibited greater sympathetic nervous system activity than the control condition. A significant index of moderated serial mediation emerged for Preoccupation with Dieting and Weight-Focused Restraint in the stress + uncertain safety condition. Though sympathetic activation decreased hunger similarly regardless of dietary restraint, only less restrained individuals significantly decreased intake. More restrained individuals ate more despite experiencing lower hunger. The disconnect between hunger and intake in more restrained eaters suggests that focus on enhancing attunement to hunger may yield greater benefit than enhancing restraint. 281 words.

Validity and reliability of the Dietary Rules Inventory (DRI)

BACKGROUND

Dietary rules are common in patients with eating disorders, and according to transdiagnostic cognitive behavioural theory for eating disorders, represent a key behaviour maintaining eating-disorder psychopathology. The aim of this study was to describe the design and validation of the Dietary Rules Inventory (DRI), a new self-report questionnaire that assesses dietary rules in patients with eating disorders.

METHODS

A transdiagnostic sample of 320 patients with eating disorders, as well as 95 patients with obesity and 122 healthy controls were recruited. Patients with eating disorders also completed the Dutch Eating Behaviour Questionnaire (DEBQ), the Eating Disorder Examination Questionnaire, the Brief Symptoms Inventory and the Clinical Impairment Assessment. Dietary rules were rated on a continuous Likert-type scale (0-4), rating how often (from never to always) they had been applied over the previous 28 days.

RESULTS

DRI scores were significantly higher in patients with eating disorders than in patients with obesity and healthy controls. Principal factor analysis identified that 55.8% of the variance was accounted for by four factors, namely 'what to eat', 'social eating', 'when and how much to eat' and 'caloric level'. Both global score and subscales demonstrated high internal and test-retest reliability. The DRI global score was significantly correlated with the DEBQ 'restrained eating' subscale, as well as eating-disorder and general psychopathology and clinical impairment scores, demonstrating good convergent validity.

CONCLUSIONS

These findings suggest that the DRI is a valid self-report questionnaire that may provide important clinical information regarding the dietary rules underlying dietary restraint in patients with eating disorders.

LEVEL OF EVIDENCE

V, descriptive study.

Life is uncertain, eat dessert first: Uncertainty causes controlled and unemotional eaters to consume more sweets

Sometimes even dieters with the best self-control overindulge. Uncertain situations may undermine the self-control of even well-controlled eaters. This study was designed to test the hypothesis that uncertainty increases unhealthy snacking. Participants were either told that they would be giving a speech, that they would be listening to a speech, or that they would find out later whether they were to give a speech or not. Among participants who typically reported good control over their eating or scored low on emotional eating, participants who were uncertain about whether they would be giving a speech ate more candy than participants who expected to not have to give a speech and even those who expected to have to give a speech. Participants who reported poor control over their eating or scored high on emotional eating did not eat significantly more when uncertain. These findings suggest that, for people who are typically able to control their eating, uncertainty increases snacking more than certainty of a negative outcome.

Effects of dietary restraint and body mass index on the relative reinforcing value of snack food

The present study examined the independent and interactive association between dietary restraint, body mass index (BMI) and the relative reinforcing value of food. Four hundred and three introductory psychology students completed questionnaires assessing age, gender, BMI, hunger, smoking status, nicotine dependence, dietary restraint, hedonic ratings for snack food and fruits and vegetables and the relative reinforcing value of snack food and fruits and vegetables. In the overall sample, results indicated a dietary restraint x BMI interaction after controlling for age, hunger, nicotine dependence, and hedonics. However, when regression models were separated by gender, the BMI x restraint interaction emerged only for females and not for males. Findings suggest that BMI moderates the relationship between dietary restraint and snack food reinforcement in females only, such that restraint and snack food reinforcement are inversely correlated in females with lower BMI, but restraint is positively correlated with snack food reinforcement in females with higher BMI. Theoretical and clinical implications of these findings are discussed.

Effects of exercise and restrained eating behaviour on appetite control

Obesity is a global epidemic; increased consumption of energy-dense food and reduced physical activity levels are likely to be the main drivers. Previous cross-sectional research has shown that sedentary males, unlike their active counterparts, are unable to compensate for previous energy intake (EI). Using a longitudinal design a 6-week exercise intervention was found to improve short-term appetite control, leading to a more ‘sensitive’ eating behaviour in response to previous EI, both acutely at a test meal and for the next 24 h. Although the mechanisms whereby acute and chronic exercise improves short-term appetite remain unknown, post-ingestive satiety peptides are likely to be involved. Acute exercise was found to increase postprandial levels of polypeptide YY, glucagon-like peptide-1 and pancreatic polypeptide but to have no impact on ghrelin, suggesting that exercise can trigger physiological changes in satiety hormone secretion that could help in appetite control and weight maintenance. In the context of an increased availability of highly-palatable food, dietary restraint may be increasingly important. Although restraint has been associated with abnormal eating behaviour, in the laboratory no counter-regulation was found in restrained eaters when presented with a buffet meal 60 min after a high-energy preload or when a pasta-meal was presented 3 h after preloading. Although restraint was not found to impact on polypeptide YY or TAG, lower postprandial glucose and insulin plasma levels were observed in restrained eaters, together with increased feelings of fullness. In conclusion, short-term appetite control seems to be favourably modified by exercise, while the impact of restraint on appetite seems to be more complex.

Neither restrained eating nor tendency toward overeating predict food consumption after tension induction

The present study investigates whether the so-called disinhibition effect is better accounted for by tendency toward overeating than by restraint. The rationale was that in mood-induction studies, so far, the disinhibition effect has only been found in studies that applied the Restraint Scale and hardly ever in studies that used other restraint scales. Tension was induced by the public-speaking method in half of 86 female college students before they participated in an alleged taste test. The Restraint Scale (RS), the Three-Factor Eating Questionnaire (TFEQ) and the Dutch Eating Behaviour Questionnaire (DEBQ) were used to measure restraint and tendency toward overeating. No differences were found between the tension and the control condition as to the amounts of food the participants ate. Also no proof of the disinhibition effect was obtained and, remarkably, tendency toward overeating did not predict the amount of food eaten. Possible explanations for these results are offered in the discussion.

Rigid and flexible control of eating behavior and their relationship to dieting status

This study examined whether or not rigid and flexible dimensions of restraint could differentiate between women who self-identified as dieting to lose weight versus those who self-identified as dieting to maintain weight. Four hundred thirty-three women responded to dichotomous questions regarding their dieting status and completed the Eating Inventory and Rigid and Flexible Control Scales (RC16 and FC12, respectively). Logistic regressions were conducted using dieting status as the dependent variable and RC16 scores, FC12 scores, susceptibility to overeating, and BMI as the independent variables. Scores on the RC16 and BMI correctly identified 73.6% of women as dieting to lose weight; scores on the RC16 and FC12 correctly identified 52.6% of women as dieting to maintain weight. Susceptibility to overeating was unrelated to dieting status. Results indicate that rigid control over eating is strongly related to dieting to lose weight and that both rigid and flexible control are related to dieting to maintain weight. This latter relationship is in need of further exploration. Results of this study support the contention that restraint and dieting are related, however, they are not equivalent constructs.

Effect of exposure to a forbidden food on eating in restrained and unrestrained women

OBJECTIVE

The current study explored the effect of availability of a forbidden food on subsequent eating behavior in restrained and unrestrained women.

METHOD

Thirty restrained and 30 unrestrained, normal-weight women were assigned randomly to one of two conditions, an experimental group that was exposed to a forbidden food (chocolate) for 24hr or a control group that was given no special intervention. At the end of the exposure period, all subjects completed an intake test of the forbidden food.

RESULTS

Although subjects were instructed not to eat the food provided for the exposure period, women in the restrained group consumed a small quantity of the chocolate, whereas unrestrained women consumed none. Intake at test was greater in the temptation than in the control condition and restrained eaters consumed more than unrestrained eaters in both conditions.

DISCUSSION

The results are discussed in terms of current theories of restrained eating and the possible interrelationships between eating regulation and cognition.

Absence of a disinhibition effect of alcohol on food consumption

Alcohol is frequently mentioned as a disinhibitor of restrained eating behavior although only a small number of studies have investigated this disinhibition effect. The present study was conducted to fill this gap. A total of 116 female college students participated in a questionnaire-based assessment and a taste-test experiment. Before the taste test, half of the participants consumed a preset amount of alcohol-laced orange juice, the other half were given plain orange juice. The dependent variable was the amount of savory crackers eaten during the taste test. The Dutch Eating Behavior Questionnaire (DEBQ), the Three-Factor Eating Questionnaire (TFEQ), and the Restraint Scale (RS) were used to measure eating behavior dimensions, which formed the independent variables in various regression analyses. No disinhibition effect was found. On the contrary, participants scoring high on restraint (DEBQ, TFEQ) proved to consume even less food than those having lower scores. Participants that rated high on the scales measuring tendency toward overeating consumed more food than participants with low scores. These results support earlier contentions that the validity of the Restraint Theory's statement that dieting leads to overeating is questionable.

Effects of manipulated palatability on appetite depend on restraint and disinhibition scores from the Three-Factor Eating Questionnaire

OBJECTIVES

The present study evaluated the effects of dietary restraint on short-term appetite in response to manipulated palatability.

DESIGN

The effects of palatability on appetite during a lunchtime meal were assessed by contrasting intake of a bland and palatable version of a simple food (within subject). To test how responses to palatability varied with restraint, these meals consumed by women were classified according to restraint (R) and disinhibition (D) scores from the Three-Factor Eating Questionnaire (TFEQ) as high R/high D (HR-HD), high R/low D (HR-LD), low R/high D (LR-HD) and low R/low D (LR-LD).

SUBJECTS

A total of 40 normal-weight women subdivided into four groups based on TFEQ scores.

MEASUREMENTS

The overall intake, appetite and hedonic ratings before, during and after the meal.

RESULTS

All groups ate similar amounts of the bland food, but the LR-HD group ate significantly more of the palatable version than the other groups, whereas HR-LD did not increase intake in response to palatability. Hunger increased on tasting the palatable food in all but the HR-LD group, and this group ended both meals more hungry/less full than the others.

CONCLUSION

Women classified as HR-LD were unresponsive to manipulated palatability, whereas those classified as LR-HD were over-responsive. These findings imply that some individuals are prone to over-respond to palatability and so are at greater risk of developing obesity, whereas others are able to resist the effects of palatability and so successfully self-restrict their food intake. Implications for obesity are discussed.

Tendency toward overeating and restraint as predictors of food consumption

Restrained eaters have repeatedly been found to overeat following a preload, which phenomenon is called the disinhibition effect. Remarkably, the disinhibition effect is only found when the restraint scale (RS) is used, and never when other measures of restraint, like the three-factor eating questionnaire (TFEQ) or the Dutch eating behavior questionnaire (DEBQ) are applied. Recent research has shown that tendency toward overeating appears to be a better predictor of food consumption than dietary restraint. The present study examines the predictive value of preload, tendency toward overeating and dietary restraint. An experiment was carried out with 209 female participants with the aim to evaluate whether the results of the study [Int J Eating Disorders 28 (2000) 333] are robust. In addition to the RS, the TFEQ and DEBQ were used to measure restraint and tendency toward overeating. Again, no disinhibition effect occurred, confirming the results of the previous study. Restraint, as measured by the three questionnaires, was not related to food consumption. In contrast, tendency toward overeating was significantly related to food consumption. Restraint theory's contentions that dieting leads to overeating might be valid for only some dieters, namely those with a high tendency toward overeating.

Ice-cream consumption, tendency toward overeating, and personality

OBJECTIVE

The exploration of the mechanisms underlying the tendency toward overeating by investigating the Dutch Eating Behavior Questionnaire (DEBQ)/Revised Eating Disorders Inventory (EDI-R) disinhibition, in sequence to the milkshake-ice cream study (van Strien, Cleven, and Schippers, in press).

METHOD

In hierarchical multiple regression analyses, the relative predictive power for ice-cream consumption was assessed, that is, emotional versus external versus bulimic eating using scales of the DEBQ and the EDI-R. In nonplanned stepwise multiple regression analyses, the association was assessed between these three types of eating behaviors and non-eating-related EDI-R scales.

RESULTS

Emotional eating was the most important variable for ice-cream consumption. External eating was borderline significant and bulimic eating nonsignificant when emotional and external eating had been partialled out. Emotional eating was best predicted by the EDI-R scales Asceticism, Interoceptive Awareness, and Social Insecurity.

DISCUSSION

Results are consistent with psychosomatic theory, which focuses on emotional eating as the result of confusion and apprehension in recognizing and accurately responding to emotional and visceral states related to hunger and satiety.

Restraint, tendency toward overeating and ice cream consumption

OBJECTIVE

The examination of the prediction of grams of ice cream eaten by preload, restraint, susceptibility toward overeating, and interaction terms.

METHOD

A milkshake-ice cream study on 200 females using the Restraint Scale (RS) and the restraint and disinhibition scales from the Three-Factor Eating Questionnaire (TFEQ) and the Dutch Eating Behavior Questionnaire (DEBQ). Restraint and tendency toward disinhibition are treated as continuous variables in hierarchical step up multiple regression analyses.

RESULTS

There was no disinhibition effect, as subjects did not overeat after the milkshake, neither in function of their restraint nor in function of their tendency toward overeating or any interactions between these. Tendency toward overeating was the most important variable for ice cream consumption. Restraint itself, the part that remained after tendency toward overeating had been partialed out, was not related to ice cream consumption. In terms of its association with ice cream consumption, the DEBQ disinhibition scale seems more promising than the TFEQ disinhibition scale.

DISCUSSION

Restraint theory seems mainly valid for dieters with a tendency toward overeating. Tendency toward overeating may even be a better predictor than restraint, opening the possibility that overeating precedes dieting.

Dietary restraint, attributional styles for eating, and preloading effects

A total of 319 undergraduates completed the Restraint Scale and an Eating Attributional Style Questionnaire (EASQ). Subsequently, 101 female students participated in the classic preloading experiment. The results indicated that restrained eating was associated with an external locus of control attribution style, particularly for indulgent food consumption (ELCifc). Partial preloading effects for Restraint were found: The amount consumed increased as a function of Restraint in the preload condition. A more complete pattern of preloading was found for the ELCifc attribution style. In addition, the relationship between Restraint and food consumed in the preload condition was no longer significant with the ELCifc attribution style partialled out. The findings supported the hypotheses that: (a) restrained eaters display an external attribution style of learned helplessness and (b) related cognitions serve as a cause of preloading effects.

Restraint, weight suppression, and self-report reliability: how much do you really weigh?

This study examined the effects of weight suppression on eating behaviors in a standard restraint ice cream taste-test paradigm. Participants were 58 female restrained eaters categorized by self-report as either high- or low-weight suppressors. Prior to the taste test, half of the participants received a milkshake preload. The amount of ice cream consumed during the taste test was the primary measure of interest. A 2 x 2 analysis of variance (ANOVA) indicated no significant differences between groups. This contradicts previously reported results in which restrained eaters consumed more following a preload than in the no-preload condition and provides further evidence that restraint is not a homogeneous construct. These results also question the use of self-report measures to determine an individual's level of weight suppression.

Eating behavior following stress in women with and without bulimic symptoms

OBJECTIVE

This study examined the effects of an interpersonal stressor on subsequent calorie intake in females with (N = 20) and without (N = 20) significant bulimic symptomatology.

METHOD

Subjects participated in two laboratory sessions that differed according to experimental condition (stress versus no stress), completed self-report measures of mood and anxiety before and after the experimental task, and were provided with an array of snack foods after each session.

RESULTS

Counter to the hypothesis, women with bulimic symptoms did not differentially increase their intake when exposed to stress. However, results for the intake of each macronutrient indicated that both bulimic and control women increased their consumption of carbohydrates following the stressor. Thus, stress was related to increased carbohydrate consumption by all subjects but did not differentially affect the consumption of women with bulimic symptoms.

CONCLUSIONS

It may be that women with bulimic symptoms are not differentially vulnerable to eating in response to stress or that current laboratory paradigms are unable to detect differences in eating following a stressor.