Unrestrained Subjects Research Articles

Stroop interference and food intake

The Stroop task is aimed at assessing attentional bias. Words are displayed one by one on a computer screen and subjects are instructed to name the color in which every word is printed. The attentional bias is supposed to be reflected in the extent to which the word meanings interfere with the speed of color naming: The longer the color naming latency, the larger the attentional bias. Experiments using this task have demonstrated attentional bias for eating and body shape-related words in bulimic, anorexic, and restrained subjects. Explanations of these results have generally been formulated in terms of restricted food intake or emotional concerns about food and body shape-related themes. In contrast, in the present article it was proposed that Stroop interference might reflect a tendency either to withdraw or approach food or body shape-related stimuli. Fifty-one subjects (25 unrestrained, 26 restrained) were administered a Stroop task containing neutral, food, and body shape-related words. There were two conditions to which subjects were randomly allocated: the "appetizer" and "no-appetizer" condition. The appetizer was a bit of pudding to be ingested by the subject just before the Stroop task. Following the Stroop task an ice cream taste test was presented in which the subjects were allowed to eat as much as they liked. The amount of ice cream eaten was registered secretly. The results show that in unrestrained subjects Stroop interference for food words was found only in the appetizer condition. Restrained subjects, however, showed a permanent interference for food words. A significant correlation of .58 between Stroop food-word interference and ice cream intake was found only in unrestrained subjects. In restrained eaters the correlation was near 0. No effect of condition or restraint was found on Stroop body shape-word interference. The findings indicate that (1) ingestion of an appetizer seems to have evoked an attentional bias for food words in nonrestraints that correlated with food intake; (2) restrained eaters showed continuous attentional bias. This appears to support the urge-to-act explanation of Stroop interference. The lack of correlation between restraints' attentional bias and ad lib food intake could have been caused by inhibition of approach which is one of the characteristics of restrained eating: The present procedure seems not to have triggered disinhibited eating in these subjects. Among other things it is concluded that Stroop interference, as a measure of "craving" triggered by food cue, might be a useful aid in assessing the risk of relapse in treated binge eating patients.

Public Self-Awareness and Success-Failure Feedback as Disinhibitors of Restrained Eating

This study investigated the role of public self-awareness and distress in disinhibiting eating. Ninety-six women who were classified as restrained or unrestrained eaters completed a computerized social perception test during which public self-awareness (low vs. high) and type of feedback (success vs. failure) were manipulated. Following the test, restrained subjects ate more than did unrestrained subjects. When public self-awareness was low, subjects who received failure feedback consumed more than those who were exposed to success feedback. An opposite pattern occurred in the high-self-awareness condition. A post hoc examination revealed that restrained subjects exhibited more regulated eating behavior when exposed to a combination of disinhibitors, whereas each disinhibitor taken separately was associated with increased consumption. Results were interpreted in terms of the self-awareness reduction model of eating.

The effects on eating of dietary restraint, anxiety, and hunger

In this study a comparison was made between the amounts eaten by restrained and unrestrained eaters following an anxiety-induction procedure. Subjects' level of perceived hunger was assessed and the interactive effects on eating of anxiety and perceived hunger were examined. Results revealed a significant three-way interaction. Unrestrained subjects did not alter their eating in response to either anxiety or hunger. When relaxed, restrained subjects ate more when hungry than when not hungry. However, in restrained subjects, anxiety appeared to counteract the disinhibiting effect of hunger, so that anxious hungry subjects ate less than relaxed hungry subjects and the same amount as relaxed subjects who were not hungry.

Dietary restraint and responsiveness to sensory-based food cues as measured by cephalic phase salivation and sensory specific satiety

Responsiveness to sensory-based food cues was examined in restrained and unrestrained, normal-weight subjects identified with the Three-Factor Eating Questionnaire. Salivary flow rate was measured with no food present and while subjects viewed hot pizza. In the presence of food, restrained eaters had a mean salivary flow rate (0.388 g/min) greater than twice that of the unrestrained eaters (0.186 g/min). During sensory specific satiety testing, subjects tasted and rated the pleasantness of 9 foods, then received a meal of either cheese and crackers or cookies. Changes in pleasantness for the tasted foods were evaluated at 2, 20, and 40 min following the meal. Both restrained and unrestrained subjects displayed similar patterns of sensory specific satiety, i.e., the pleasantness foods which were eaten decreased relative to foods tasted but not eaten. These patterns were unaffected by the type of food consumed in the test meal. These data demonstrate that restrained eaters show moderately enhanced salivary responses but no changes in sensory-specific satiety to food stimuli, suggesting that heightened responsiveness to the sensory properties of foods may not be a generalized phenomenon in restrained eaters.

Mechanical Restraint Use and Fall-related Injuries among Residents of Skilled Nursing Facilities

To evaluate the association between mechanical restraint use and the occurrence of injurious falls among persons residing in skilled nursing facilities. Prospective observational cohort study. Twelve skilled nursing facilities in southern Connecticut. The 397 persons who were mobile and unrestrained at baseline. Restraint use was defined both as the number of days restrained and as "never," "intermittently," or "continually" restrained. The primary outcome measure was the occurrence of a serious fall-related injury. Analyses were done on the entire cohort as well as on a subgroup hypothesized as having a high risk for falls. During one year of follow-up, 122 subjects (31%) became restrained, 83 intermittently and 39 continually. A serious fall-related injury was experienced by 5% (15 of 275) of unrestrained, compared with 17% (21 of 122) of restrained, subjects (chi-square = 12.478; P less than 0.001). Restraint use remained independently associated with serious injury after adjusting for other factors, both in the entire cohort (adjusted odds ratio, 10.2; 95% CI, 2.8 to 36.9) and in the high-risk subgroup (adjusted odds ratio, 6.2; CI, 1.7 to 22.2). Among the 305 subjects who experienced two or fewer falls, the proportion having a serious injury was 15% for restrained subjects compared with 4% for unrestrained subjects (difference in proportions 11%, CI, 4% to 17%), whereas the comparable proportions for the 92 subjects who experienced more than two falls were 20% and 16%, respectively. Results were similar in the high-risk subgroup. Mechanical restraints were associated with continued, and perhaps increased, occurrence of serious fall-related injuries after controlling for other injury risk factors. Study results suggest the need to consider whether restraints provide adequate, if any, protection.

Relationship of perceived macronutrient and caloric content to affective cognitions about food in eating-disordered, restrained, and unrestrained subjects

Cognitive sets concerning food were examined in eating-disorder patients and in restrained and unrestrained control subjects. Subjects rated 38 common foods for preference, presence or absence of guilt and danger, preferred monthly frequency, and caloric, fat, and carbohydrate content. Cognitive ratings were examined based upon the individual's perceived amounts of calories and macronutrients. Hedonic ratings of foods perceived as high in fat or calories were different in patients with current or past anorexia and did not change with treatment. The fat-calorie aversions seen in these patients, therefore, appear to be stable trait characteristics of the disorder. Guilt and danger were perceived as separate constructs by unrestrained and restrained control subjects but not by patients. Perceived high amounts of calories or fat triggered stronger feelings of guilt and danger for restrained control subjects and patients (especially bulimic patients) as compared with unrestrained control subjects. The patients' expressions of guilt and danger improved with treatment.

Accuracy of respiratory inductive plethysmograph in measuring tidal volume during sleep

Respiratory inductance plethysmography (RIP) has been widely used to measure ventilation during sleep, but its accuracy in this role has not been adequately tested. We have thus examined the accuracy of the RIP by comparing tidal volume measured with RIP with that measured by a pneumotachograph in eight unrestrained normal subjects during sleep. We have also studied the effect of posture on the accuracy of the RIP. In all sleep stages the correlation between RIP tidal volume measurements and expired volume showed relatively poor correlations (mean r = 0.49-0.60), and the bias of the measurements varied widely. Changes in posture altered the correlations between the two measurements, with no systematic differences between positions. When the subjects resumed a position, the 95% confidence intervals of tidal volume measurement did not overlap the original confidence limits in that posture on 13 of 25 occasions. This study shows that the RIP does not accurately measure tidal volume during sleep in unrestrained subjects and should only be used for semiquantitative assessment of ventilation during sleep.

Restrained eating (weight concerns) in the general population and among students

Restrained eating in a random sample of 2115 adults was studied as part of a broad health survey. Interview questions were derived from Herman and Polivy's Restraint Scale (1975, 1980). Restrained eaters were predominantly normal and overweight women under 65 years of age. Significantly more women (20.7%) than men (8.9%) were restrained eaters. A similar prevalence of restrained eating was observed in students and same-age nonstudents. There was substantial overlap (but not congruence) between respondents who were dieting and being a restrained eater. Binge eating was reported more often by restrained eaters than unrestrained subjects. The relationship between restrained eating and bulimia-related atypical eating disorders is discussed.

Effects of physical threat and ego threat on eating behavior.

Restrained and unrestrained subjects were subjected to one of three distress manipulations prior to an ad lib taste task. The physical fear threat (anticipated electric shock) significantly decreased unrestrained subjects' eating and slightly increased restrained subjects' eating. Both ego threats (failure at an easy task or anticipating having to give a speech in front of an evaluative audience) significantly increased restrained subjects' eating but did not significantly suppress unrestrained subjects' eating. This pattern supports the proposition that physical fear differs from more general dysphoria in its effects on eating, perhaps because of the divergent effects of these two types of distress on eating control mechanisms, which in turn differ in restrained and unrestrained eaters.

Good and bad dieters: Self-perception and reaction to a dietary challenge

The influence of self-perceived dieting ability on restrained eaters was tested in a study directly manipulating such self-perceptions. The hypothesis that a dieter's perception of her own dieting ability would affect how she handled an acute challenge to her diet was tested by manipulating the restrained eater's view of themselves as good or bad dieters. Restrained and unrestrained subjects were given ad lib access to ice cream after either a high-calorie preload or no preload. As predicted, dieters induced to see themselves as “good” ate less after the preload than did dieters whose self-perception was not manipulated, but dieters who saw themselves as “bad” also reduced their intake. Over the next week, restrained subjects in general lost more weight, with those who had been led to focus on their dieting ability in the face of a challenge, being mainly responsible for this effect.

Restraint, weight loss, and variability of body weight.

Restrained and unrestrained subjects (n = 24) were weighed daily for a 6-week period and again 6 months later in order to determine whether dietary restraint or relative body weight is the better predictor of weight variability. Restraint was a significantly better predictor of naturally occurring weight fluctuations than was relative body weight. Furthermore, the 2 factors of the Restraint Scale, Concern for Dieting and Weight Fluctuations, were both significant predictors of weight variability. We propose that exaggerated weight fluctuations are not a natural concomitant of higher body weight but possibly the consequence of a cycle of dieting and overeating, which seems to preclude actual weight loss.

Reduction in accident injury severity in rear seat passengers using restraints

A prospective study of 441 rear seat occupants seen following road traffic accidents compared injury severity in the 411 unrestrained and 30 restrained subjects. Using ridit analysis, the injury severity score showed far less injury among restrained subjects (P = 0.0001). All 11 deaths and 176 of the 178 most severe injuries occurred in the unrestrained group. One restrained (3 per cent) subject was admitted overnight and 64 unrestrained (16 per cent) subjects required admission; two-thirds required a prolonged admission (mean = 13 days). Fractures, major bruises, abrasions and lacerations were almost confined to unrestrained passengers, 221 events compared with two among restrained passengers. Twenty-three unrestrained subjects were ejected, nine of whom were killed. We conclude that the use of rear seat restraints greatly reduces injury severity and should be compulsory for rear seat occupants as it is for front seat occupants.

Unobtrusive monitoring of ventilation in unrestrained subjects

Unobtrusive monitoring of ventilation in unrestrained subjects

Restraint and internal responsiveness: Effects of placebo manipulations of hunger state on eating.

Restrained and unrestrained subjects were given a "vitamin" (placebo) prior to an ad-lib taste test. Subjects were either told nothing about the placebo or told that previous subjects had reported that the vitamin had made them feel either hungry or full. As predicted, restrained subjects, in two separate studies, behaved in accordance with placebo messages, eating more when given "hungry" messages than when given "full" messages. Unrestrained subjects showed an apparent reverse-placebo effect; they ate less ice cream when given "hungry" information than when given "full" information. Hunger ratings did not parallel eating behavior; possible explanations for this discrepancy are considered. We conclude that unresponsiveness to internal hunger state, and an overreliance on external cognitive cues, characterizes restrained but not unrestrained individuals.

Effects of dietary restraint, obesity, and gender on holiday eating behavior and weight gain.

This investigation evaluated the impact of dietary restraint, relative weight, and gender on holiday eating behavior and weight gain. 65 Ss (31 men and 34 women) completed detailed food records for the 2 days before, the 4 days during, and the 2 days after the Thanksgiving weekend. Results indicated increased eating during the Thanksgiving holiday, with men eating more than women and the obese eating less than the nonobese. There was also a significant Total Restraint X Weight X Time interaction, with unrestrained normal-weight subjects behaving similarly to high-restrained overweight subjects over time. There was also a highly reliable Total Restraint X Sex X Time interaction. The most striking finding from this interaction was that high-restrained women displayed decreases in their dietary intake over time. Correlational analyses revealed that restraint scores were negatively associated with dietary intake over the 8-day period but were positively associated with weight gain. The implications for dieting, eating behavior, and energy balance are discussed.

Body image assessment in patients with bulimia nervosa and normal controls

A video image distortion technique was used to assess differences in the perceived (actual) and ideal body size and shape among female patients with bulimia nervosa (n = 12) and two groups of nondepressed, non-eating-disordered women classified as restrained (n = 12) or unrestrained (n = 12) eaters. On the majority of measures of body image the bulimic patients and restrained eaters differed from the unrestrained eaters but did not differ significantly from each other. The results do not show that body image disturbance, at least as it was assessed in this study, discriminates bulimics from appropriate nonclinical controls. In absolute terms the bulimics were more accurate than the controls in estimating their current body size. The latter underestimated their body size. However, the bulimics' estimates were higher in relation to the controls. The discrepancy between perceived body size and ideal body size also differentiated the groups, with the bulimic and restrained subjects exhibiting significantly more discrepancy between perceived and ideal than the unrestrained subjects. Significant correlations between body size estimation and self-report of body satisfaction suggests that evaluation and perception of body are closely associated.

Physiological and self-report responses of restrained and unrestrained eaters

According to the theory of dietary restraint, restrained normal-weight individuals are similar to the obese in terms of hyperresponsiveness to external stimuli, and, perhaps, presumed internal underresponsiveness, differing only in the extent to which body weight has been successfully regulated. The present study sought to clarify the mechanism for this hyperemotionality and to investigate whether the presumed underresponsiveness to internal nutritional cues also extends to internal (i.e., autonomic) cues for restrained eaters. Restrained and unrestrained subjects were exposed to a cognitive and an interpersonal stressor during which physiological and self-report measures of anxiety were recorded. No evidence for actual physiological differences between restrained and unrestrained eaters were found. However, the results indicated that unrestrained subjects demonstrated a significant relationship between physiological and self-report measures of anxiety, while both normal weight and obese restrained eaters shows no positive relationship between physiological states and self-rated anxiety.

Is there a metabolic component to counterregulation?

A highly structured test meal situation was used to examine the metabolic and behavioral response of restrained and unrestrained eaters to a disguised calorific preload. Both restrained and unrestrained eaters ate initially more quickly after drinking a disguised glucose preload, compared with those who drank a glucose-free preload. Restrained eaters showed a comparatively greater increase in rate of eating, which tended to persist as a greater overall food consumption. The unrestrained group compensated for their initially greater consumption by eating less later in the meal. The excess eating occurred in conjunction with the release of excess insulin compared with circulatory glucose in response to the preload. In the unrestrained subjects, this declines together with the compensatory decrease in food consumption. For restrained eaters, the elevation of insulin/glucose ratio persisted and was comparatively greater, in conjunction with a persistent and relatively greater enhancement of food intake. Subjective reports and ratings indicated that the subjects were aware of neither the presence nor the behavioral and metabolic effects of the preload. The results suggest a possible metabolic component to the phenomenon of counterregulation.

Self-esteem, restraint, and eating behavior.

The mediating influence of self-esteem on disinhibited eating was assessed in restrained and unrestrained subjects. Self-esteem was unrelated to the eating behavior of unrestrained subjects following a preload, but did moderate the disinhibitory effects of a preload on restrained subjects. Specifically, only those restrained subjects with low self-esteem displayed disinhibited eating after a preload. Theoretical and practical implications of this finding were discussed.

Cognitions and self-talk during food intake of restrained and unrestrained eaters

In the present study, restrained subjects failed to regulate their ice-cream intake after a preload of milkshakes, while unrestrained subjects succeeded. Restraint was not related to irrational thinking patterns, as reflected by scores on the Rational Behavior Inventory (RBI) and the Irrational Belief Test (IBT). During the disinhibitive challenge, the self-talk of the subjects was recorded on tape. Restrained subjects in a disinhibition challenge, i.e. preload condition, were expected to report significantly more disinhibitive thoughts than restrained subjects in a no-preload condition. Unrestrained subjects were expected to report no disinhibitive self-talk at all. The authors failed to find experimental confirmation for the widely held view that dichotomous thoughts such as “I've blown my diet, I might as well continue to eat” disinhibit restrained eaters.