The single-item meal as a measure of binge-eating behavior in patients with bulimia nervosa.

To determine whether the characteristics of binge eating could be observed in a single-item meal, in a laboratory, patients with bulimia nervosa and controls ate two single-item meals and two multiple-item meals. When they were instructed to binge eat, the patients ate significantly more and for a longer time on both single- and multiple-item meals than did controls. When they were instructed not to binge, intakes of the two groups did not differ. Controls, but not most of the patients, showed deceleration in their eating rate when they were asked to binge. Intakes of the single- and multiple-item meals were significantly correlated for the patients under both sets of instructions. These results are consistent with previous reports in indicating that patients with bulimia nervosa eat differently from controls and suggest that a single-item meal can be used to examine the characteristics of binge eating in patients with bulimia nervosa.     

Serotonergic dysfunction across the eating disorders: relationship to eating behaviour,purging behaviour,nutritional status and general psychopathology

BACKGROUND: Several recent studies have pointed to a dysfunction of serotonin transmission in patients with eating disorders. Notwithstanding, it is not known whether serotonergic abnormalities are related primarily to eating and/or purging behaviour, nutritional status or general psychopathological dimensions. Therefore, by using a validated neuroendocrine strategy, we investigated central serotonergic function in patients with anorexia nervosa, bulimia nervosa or binge-eating disorder who differ on the above parameters. METHODS: Plasma prolactin response to D-fenfluramine (30 mg p.o.) or placebo was measured in 58 drug-free female volunteers, comprising 15 underweight anorexic women, 18 bulimic women, 10 women with binge-eating disorder and 15 female healthy controls. Behavioural assessment included ratings of eating disorder symptoms, depression, aggression and food-related obsessions and compulsions. RESULTS: A significantly decreased prolactin response to D-fenfluramine was found in underweight anorexic women and in bulimics with high frequency bingeing ( > 2 binge episodes/day), but not in patients with binge-eating disorder or in bulimics with low frequency bingeing (< I binge episode/day). In the whole bulimic group, a negative correlation emerged between frequency of bingeing and prolactin response. No significant correlation was found between physical or psychopathological measures and the hormonal response in any group. CONCLUSIONS: These results confirm our previous findings of an impaired serotonergic transmission in underweight anorexics and in bulimics with high frequency bingeing, but not in patients with less severe bulimia nervosa. Moreover, they show, for the first time, that the hypothalamic serotonergic system is not altered in women with binge-eating disorder.     

Effect of eating rate on binge size in Bulimia Nervosa

Bulimia Nervosa (BN) is an eating disorder characterized by recurrent episodes of binge eating. During binge eating episodes, patients often describe the rapid consumption of food, and laboratory studies have shown that during binges patients with BN eat faster than normal controls (NC), but the hypothesis that a rapid rate of eating contributes to the excessive intake of binge meals has not yet been experimentally tested. The aim of this study was to assess the effect of eating rate on binge size in BN, in order to determine whether binge size is mediated, in part, by rate of eating. Thirteen BN and 14 NC subjects were asked to binge eat a yogurt shake that was served at a fast rate (140 g/min) on one occasion and at a slow rate (70 g/min) on another. NC subjects consumed 169 g more when eating at the fast rate than when eating at the slow rate. In contrast, consumption rates failed to influence binge size in patients with BN (fast: 1205 g; slow: 1195 g). Consequently, there was a significant group by rate interaction. As expected, patients with BN consumed more overall than NC subjects (1200 g vs. 740 g). When instructed to binge in the eating laboratory, patients with BN ate equally large amounts of food at a slow rate as at a fast rate. NC subjects ate less at a slow rate. These findings indicate that in a structured laboratory meal paradigm binge size is not affected by rate of eating.     

Visceral protein and hematological status of women with bulimia nervosa and depressed controls

Serum visceral protein and hematological indices and their behavioral and clinical correlates were determined in women with bulimia nervosa and depressed controls. One hundred and fifty-two women who met DSM-IV criteria for bulimia nervosa and 68 women with DSM-IV major depression completed a structured clinical interview and had blood samples drawn prior to admission to outpatient treatment programs. Albumin and prealbumin concentrations were lower in the depressed women, possibly due to recent weight loss. Elevated transferrin values suggested mild iron deficiency in nearly one-fifth of women with bulimia nervosa. Of women with bulimia nervosa, the 10.7% who had hemoglobin and 5.1% who had vitamin B12 levels below the normal range were not distinguishable on measures of body mass index, binge eating, vomiting, or restriction frequency. The 4.3% with low prealbumin levels experienced significantly more episodes of binge eating and vomiting in the prior fortnight than those with normal values. Frequency of vomiting was also inversely associated with albumin concentration. Hamilton Depression Rating Scale scores were inversely and linearly related to serum vitamin B12. Lower B12 levels in those with alcohol abuse/dependence did not explain the association between B12 and HDRS scores. No hematological indices were related to body mass index, binge eating or restriction frequency, or restriction intensity. In summary, women with bulimia nervosa do not appear to be at greater risk of visceral protein or hematological abnormalities than psychiatric controls. It is suggested that a high frequency of vomiting and alcohol abuse/dependence, increases the risk of subclinical malnutrition in women with bulimia nervosa, and that poor vitamin B12 nutriture may interfere with the functioning of the serotonergic or catecholaminergic systems and contribute to depressive symptoms in bulimia nervosa.     

Psychological, hormonal and biochemical changes following carbohydrate bingeing: a placebo controlled study in bulimia nervosa and matched controls

The responses of thirteen patients with bulimia nervosa and sixteen controls matched for age and weight are described following the ingestion of a carbohydrate and a calorie-free placebo mixture in simulated binges. Psychological, hormonal and biochemical parameters were measured before and at 15 minute intervals for two hours after the simulated binge. At baseline, the bulimics were clearly more symptomatic than the controls. The control population showed a specific satiating effect of carbohydrate upon hunger ratings. Bulimic patients responded differently showing a blunting of the normal sensation of hunger and an enhanced rating for nausea. Prolactin, growth hormone (GH) and cortisol failed to show a carbohydrate-mediated stimulation in either population. The bulimic patients showed a different pattern of GH release, but this was independent of the challenge condition. Large neutral amino acid (LNAA) levels fell following carbohydrate ingestion, but produced an increase of up to 20% in the tryptophan: LNAA ratio in both bulimic patients and the control group. Thus, while this increase in tryptophan availability failed to provoke hormone release, the time course of the carbohydrate specific effect on the sensations of hunger and nausea is compatible with a mechanism based on increased tryptophan availability. The confusion of satiety with nausea may provide a useful focus for the future treatment of patients with bulimia nervosa.     

A new animal model of binge eating: key synergistic role of past caloric restriction and stress

Dieting and stress are important in the etiology and maintenance of eating disorders, and dieting strongly predicts stress-induced overeating in humans. We hypothesized that caloric restriction and stress interact in a unique manner to promote binge eating. To test this hypothesis, a group of young female rats were cycled through a restriction period (4 days of 66% of control food intake) followed by 6 days of free feeding prior to being stressed by acute foot shock. After three of these cycles, the food intake of rats exposed only to restriction (R), or only to stress (S), did not differ from controls. However, R+S rats that were restricted and refed, despite normal body weight and food intake after free feeding, engaged in a powerful bout of hyperphagia when stressed (Experiment 1). The R + S effect was replicated in an older group of rats (Experiment 2). The hyperphagia was characteristically binge-like, it constituted a 40% selective increase in highly palatable (HP) food (P < .001) over a discrete period of time (within 24 h post-stress), and reflected feeding for reward (higher HP:chow ratio) over metabolic need as occurred after restriction (higher chow:HP ratio). Subsequent experiments revealed that binge eating did not occur if only chow was available (Experiment 3) or if restriction-refeeding (R-R) did not proximally precede stress (Experiment 4). Experiment 5 revealed that a history of R-R cycles followed by only one stress episode was sufficient to increase intake to 53% above controls as early as 2 h after stress (P < .001). This animal model of binge eating should facilitate investigations into the neurochemical changes induced by dieting and environmental stress to produce disordered eating and provide a preclinical tool to test preventive strategies and treatments more relevant to bulimia nervosa, multiple cases of binge eating disorder (BED) and binge-purge type anorexia nervosa.     

Changes in rats' meal patterns as a function of the caloric density of the diet

Rats in a laboratory foraging paradigm were offered each of four diets which differed in caloric density, and intakes, meal frequencies, meal sizes, and eating rates were monitored. The rats maintained a constant daily caloric intake by eating more frequent, larger meals of the lower density foods. However, caloric meal size was not regulated, and significant correlations between meal size and the length of the post-meal interval were rarely found. The 24-hour pattern of calorie intake was the same regardless of diet. Higher-calorie foods were consumed at a faster rate within meals than were lower-calorie foods. The feeding patterns observed suggest that caloric intake may be regulated over a time frame of several meals rather than on a meal-to-meal basis.     

Analysis of feeding patterns in normal and vagotomized rabbits.

Spontaneous meal sizes, intermeal intervals, and 24 hr feeding rhythms were monitored in normal and 60 day recovered vagotomized rabbits fed solid laboratory chow. Mean sizes of meals and intermeal intervals, and the circadian distribution of food intake did not differ between the two groups, but vagotomy was associated with increased frequencies of both smaller and larger than average meals. Positive meal to postmeal interval correlations were evident in intact but not vagotomized animals, whereas vagotomized animals displayed a meal to premeal interval correlation in the light phase that was not present in normal rabbits.     

Impaired cholecystokinin secretion in bulimia nervosa

Bulimia nervosa is a prevalent disorder of unknown cause, characterized by recurrent episodes of uncontrollable eating. In the light of recent evidence that the gastrointestinal hormone cholecystokinin induces satiety and reduces food intake in laboratory animals and humans, we investigated the hypothesis that abnormalities in cholecystokinin secretion and satiety may occur in patients with bulimia and contribute to their disturbed eating patterns. Blood levels of cholecystokinin and subjective satiety were measured in 14 women with bulimia and 10 normal women before and after a mixed-liquid meal. The total integrated plasma cholecystokinin response to eating was significantly impaired in patients with bulimia (P less than 0.05) as was postprandial satiety. Fasting cholecystokinin levels were similar in both populations (approximately 0.8 pmol per liter). After eating, however, mean (+/- SEM) peak plasma cholecystokinin levels increased to 4.1 +/- 0.9 pmol per liter in normal controls but to only 2.1 +/- 0.2 pmol per liter in patients with bulimia nervosa (P less than 0.05). After an open trial of tricyclic antidepressants in a subgroup of five patients with bulimia, the postprandial cholecystokinin response to eating increased significantly, to 6.6 +/- 1.2 pmol per liter (P less than 0.05), and there was an increase in the satiety response. We conclude that patients with bulimia do not have normal satiety and have impaired secretion of cholecystokinin in response to a meal. Preliminary evidence suggests that both these abnormalities may be improved by treatment with tricyclic antidepressants.     

The olfactory control of meal pattern in rats

The role of the olfactory input in the control system regulating the free food intake of rats has been investigated. In a first experiment it was shown that the mean daily intake of 20 adult male and female rats, made anosmic by the bilateral ablation of olfactory bulbs, did not change significantly after surgery. But, as a result of the bulbar removal, the day to day fluctuation of this daily intake was significantly increased. In a second experiment the pre and postoperative recording of the daily feeding pattern (meal size and intervals) revealed that the olfactory bulbs ablation induced a more or less persistant and typical nibbling pattern. The stereotaxic electrolytic lesion of the cortico-medial amygdaloid olfactory projection, interrupting one of the olfacto-hypothalamic pathways, induced the same disrupted feeding pattern. The results are discussed in relation to control systems regulating meal sizes and meal to meal intervals in normal rats. It is suggested that the orosensory and particularly the olfactory control is responsible for determining the normal feeding pattern made of large and consistant meals followed by long intervals of nonfeeding.     

QT interval and QT dispersion in eating disorders

BACKGROUND: Eating disorders are thought to be risk factors for cardiac sudden death secondary to arrhythmia. Results in previous studies on QT interval and QT dispersion, markers of fatal arrhythmia, have been inconsistent. METHODS: We prospectively examined 179 female eating disorder patients, being over 18 years old and diagnosed according to the DSM-IV criteria between January 1995 and December 2002, and 52 healthy women. Patients with abnormal plasma electrolytes or taking medications that might influence the electrocardiogram (ECG) were excluded from the study. QT intervals were corrected for heart rate using Bazett's formula and the nomogram method, which is more reliable at extremely low heart rates than Bazett's formula. QT dispersion was measured as the difference between the longest and shortest QT intervals. QT intervals and QT dispersion in each patient group were compared with those in the control group. RESULTS: The 164 eligible patients consisted of 43 patients with anorexia nervosa restricting type, 35 with anorexia nervosa binge eating/purging type, 63 with bulimia nervosa purging type, and 23 with bulimia nervosa non-purging type. There was no significant difference in age between eating disorder patients and controls. QT interval and QT dispersion were significantly longer in all eating disorder subtypes than in the control group. QT interval and QT dispersion were significantly correlated with the rate of body weight loss in bulimia nervosa. CONCLUSIONS: QT interval and QT dispersion were prolonged in both anorexia nervosa and bulimia nervosa. Examination of ECG in eating disorder patients without extremely low body weight also appears to be clinically important.     

Characteristics common to females who exhibit anorexic or bulimic behavior: a review of current literature.

This paper reviews recent literature on the characteristics of females who exhibit anorexic or bulimic symptoms. Although researchers categorize bulimics as either binge/restrictors or binge/purgers, this paper does not distinguish between the two with regard to characteristics. Personal, cognitive, and physical characteristics, as well as external influences, are examined for each. An additional purpose of the paper is to provide an overview of risk factors that may predispose an individual to bulimia nervosa or anorexia nervosa.     

Co-occurrence of eating disorders and alcohol use disorders in women: a meta analysis

Summary This meta analysis involved 41 studies published between January of 1985 and May of 2006, which examined the co-occurrence of eating disorders (ED) and alcohol use disorders (AUD) in women. Studies were reviewed and a quantitative synthesis of their results was carried out via the calculation of standardised effect sizes. Direction and strength of the relationships between AUD and specific disordered eating patterns were examined. Heterogeneity of reported results was also assessed and examined. Only 4 out of 41 studies reported negative associations between ED and AUD. The magnitude of the associations between eating-disordered patterns and AUD ranged from small to medium size and were statistically significant for any ED, bulimia nervosa (BN)/bulimic behavior, purging, binge eating disorder (BED) and eating disorders not otherwise specified (EDNOS). No association was found between anorexia nervosa (AN) and AUD. The magnitude of the association between BN and AUD was the most divergent across studies and those between each of BED and dietary restriction and AUD were the most consistent across studies. Reported associations of different patterns of disordered eating and AUD were generally weakest and most divergent when participants were recruited from clinical settings and strongest and most homogeneous when participants were recruited from student populations.     

The prevalence of DSM-IV personality pathology among individuals with bulimia nervosa, binge eating disorder and obesity

BACKGROUND: There are numerous reports of personality disorder pathology in different eating disorders. However, few studies have directly compared personality pathology in bulimia nervosa, binge eating disorder and obesity. The present study examines group differences in DSM-IV personality pathology, considering the potential utility of understanding personality disorders in terms of diagnosis and dimensional scores. METHOD: Eating disorder diagnoses were established using the Eating Disorder Examination interview. Thirty-five bulimia nervosa patients, 15 binge eating disorder patients and 37 obese patients were assessed and compared on the International Personality Disorder Examination using categorical and dimensional personality disorder scores. RESULTS: For most personality disorders, there was a dichotomy of binge eaters versus non-binge eaters. In contrast, there was a continuum of severity in borderline personality disorder pathology between the groups. The dimensional system of measurement of personality pathology allowed for clearer differentiation between the groups. CONCLUSION: The study strongly indicates that personality disorder difficulties are present in patients who binge eat, while obese patients who do not binge eat display significantly less personality disorder pathology. Assessment of bulimia nervosa, binge eating disorder and obesity needs to address personality disorders and pathology. Dimensional markers of personality pathology can be used to supplement categorical diagnoses, providing information about the traits that underlie diagnosis.     

The shape of the cumulative food intake curve in humans, during basic and manipulated meals

The shape of the cumulative food intake curve of normal weight and obese women was studied during solid food lunches, artificially prolonged meals, and energetically enriched meals eaten in a laboratory setting. Subjects (86 normal weight, 50 obese) displayed consistent eating behaviour over 3-6 repeated meals, with marked differences between individuals. Aspects of eating behaviour were reflected in decelerated and nondecelerated (or linear) cumulative intake curves depending on changes or no changes in eating rate during the course of a meal, respectively. A change in eating rate was generally related to decrease in bite size, with bite rate remaining constant, from the third temporal quarter of the meal onwards, resulting in a decelerated cumulative intake curve. The nondecelerated (linear) cumulative intake curve does not show this change in eating rate: in the first three temporal quarters bite size and bite rate were constant, whereas in the fourth temporal quarter bite size decreased slightly, compensated by a small increase in bite rate. Intraindividual ranges for meal parameters such as chewing time per bite, bite interval and initial eating rate indicated consistency of individual eating behaviour. In manipulation experiments with a subset of 21 subjects in which meals were artificially prolonged by an interval of 8 min, the cumulative intake curves did not differ significantly from the original cumulative intake curves in 10 nondecelerated (linear) eaters, but showed a change towards nondecelerated curves in 8 out of 11 decelerated eaters.(ABSTRACT TRUNCATED AT 250 WORDS)     

Eating behavior in eating disorders: response to preloads

Eating behavior in eating-disordered subjects was investigated by recording food intake and subjective ratings following three preloads differing in calories, weight and connotation. Subjects were patients with a DSM-IIIR diagnosis of anorexia nervosa or bulimia nervosa and nonpatient volunteers (normal-weight or overweight dieters, and normal-weight nondieters). After all preloads, anorectics ate significantly less than all other subjects except normal-weight dieters, and anorectics rated hunger and desire to eat consistently lower and fullness greater than all other subjects. When analysis of intake was adjusted for body weight, anorectics and normal-weight dieters still consumed significantly less than controls. Anorectics selected foods that were lower in fat and carbohydrate and ate a larger proportion of calories as protein than the other subjects. All groups decreased subsequent intake after the high-calorie preload except bulimics. This study demonstrates that the regulatory capacity of eating-disordered individuals can be investigated and that aberrant eating behavior was observed.     

De-stabilization of the positive vago-vagal reflex in bulimia nervosa

Bulimia nervosa is characterized by consuming large amounts of food over a defined period with a loss of control over the eating. This is followed by a compensatory behavior directed at eliminating the consumed calories, usually vomiting. Current treatments include antidepressants and/or behavioral therapies. Consensus exists that these treatments are not very effective and are associated with high relapse rates. We review evidence from literature and present original data to evaluate the hypothesis that bulimia involves alterations in vago-vagal function. Evidence in support of this include (1) laboratory studies consistently illustrate deficits in meal size, meal termination, and satiety in bulimia; (2) basic science studies indicate that meal size and satiation are under vagal influences; (3) anatomical, behavioral and physiological data suggest that achieving satiety and the initiation of emesis involve common neural substrates; (4) abnormal vagal and vago-vagal reflexive functions extend to non-eating activational stimuli; and (5) studies from our laboratory modulating vagal activation have shown significant effects on binge/vomit frequencies and suggest a return of normal satiation. We propose a model for the pathophysiology of bulimia based upon de-stabilization of a bi-stable positive vago-vagal feedback loop. This model is not meant to be complete, but rather to stimulate anatomical, psychobiological, and translational neuroscience experiments aimed at elucidating the pathophysiology of bulimia and developing novel treatment strategies.     

Metabolism and endocrine secretion in response to a test meal in normal-weight bulimic women

This study assessed metabolism and endocrine secretion in normal-weight bulimic women by monitoring several digestion-related measures in the fasting state and in response to two test meals that were isocaloric but varied in degree of forbiddenness. No consistent physiological disturbances were apparent in bulimics. Their fasting electrolytes, plasma glucose, insulin, and free fatty acids were normal. Furthermore, while the two test meals resulted in different profiles of postabsorptive glucose and postprandial secretion, the two groups did not differ in their profiles. The results suggest that physiological disturbances such as disturbed glucose homeostasis or insulin secretion generally attributed to populations with eating disorders may not be apparent in normal-weight bulimics. The relevance of these findings to the etiology and treatment of normal-weight bulimia is discussed.     

Binge Eating Scale: Further Assessment of Validity and Reliability1

Validity of the Binge Eating Scale (BES), used to measure binge eating severity in overweight binge eaters, was examined using food records. A sample of 56 nonpurge binge eating women completed the BES and 28-day food records. Self-identified binges were classified as subjective when less than 1,000 calories were consumed and as objective when 1,000 calories or more were consumed. Binge severity was measured by total number of binge calories, binge episodes, and binge days over 28 days. BES scores had significant, moderate associations between subjective and objective binge eating severity. In contrast, BES scores were not related to total caloric intake. The BES was unable to distinguish between subjective and objective binge eating, which is essential for diagnostic purposes.     

Personality characteristics of women before and after recovery from an eating disorder

BACKGROUND: Previous studies of personality characteristics in women with eating disorders primarily have focused on women who are acutely ill. This study compares personality characteristics among women who are ill with eating disorders, recovered from eating disorders, and those without eating or other Axis I disorder pathology. METHOD: Female participants were assessed for personality characteristics using the Temperament and Character Inventory (TCI): 122 with anorexia nervosa (AN; 77 ill, 45 recovered), 279 with bulimia nervosa (BN; 194 ill, 85 recovered), 267 with lifetime histories of both anorexia and bulimia nervosa (AN + BN; 194 ill, 73 recovered), 63 with eating disorder not otherwise specified (EDNOS; 31 ill, 32 recovered), and 507 without eating or Axis I disorder pathology. RESULTS: Women ill with all types of eating disorders exhibited several TCI score differences from control women, particularly in the areas of novelty-seeking, harm avoidance, self-directedness, and cooperativeness. Interestingly, women recovered from eating disorders reported higher levels of harm avoidance and lower self-directedness and cooperativeness scores than did normal control women. CONCLUSIONS: Women with eating disorders in both the ill and recovered state show higher levels of harm avoidance and lower self-directedness and cooperativeness scores than normal control women. Although findings suggest that disturbances may be trait-related and contribute to the disorders' pathogenesis, additional research with more representative community controls, rather than our pre-screened, normal controls, is needed to confirm these impressions.