Average total energy expenditure in anorexia nervosa, bulimia nervosa, and healthy young women

High levels of physical activity in female adolescents with anorexia nervosa: medical and psychopathological correlates

PURPOSE

While overexercise is commonly described in patients who experience anorexia nervosa (AN), it represents a condition still underestimated, especially in the paediatric population.

METHOD

The present study aims at assessing the possible associations between levels of physical activity (PA) and clinical features, endocrinological data and psychopathological traits in a sample of 244 female adolescents hospitalised for AN subdivided into two groups according to PA levels (high PA vs. no/low PA). The two groups were compared through multivariate analyses, while multiple regression analysis was conducted to determine whether physical activity predict specific outcomes.

RESULTS

No significant differences were found between the two groups in terms of last Body Mass Index (BMI) before illness, BMI at admission and disease duration, while a difference emerged in delta BMI(rapidity of weight loss), significantly higher in high-PA group (p = 0.021). Significant differences were observed in Free triiodothyronine- (p < 0.001), Free thyroxine (p = 0.046), Follicle-stimulating hormone (p = 0.019), Luteinising hormone (p = 0.002) levels, with values remarkably lower in high-PA group. Concerning psychopathological scales, the high-PA group showed worst Children's Global Assessment Scale (CGAS) scores (p = 0.035). Regression analyses revealed that higher PA predicts higher delta BMI (p = 0.021), presence of amenorrhea (p = 0.003), lower heart rate (p = 0.012), lower thyroid (Free triiodothyronine p < 0.001, Free thyroxine p = 0.029) and gynaecological hormones' levels (Follicle-stimulating hormone p = 0.023, Luteinising hormone p = 0.003, 17-Beta estradiol p = 0.041). Concerning psychiatric measures, HPA predicts worst scores at CGAS (p = 0.019), and at scales for evaluation of alexithymia (p = 0.028) and depression (p = 0.004).

CONCLUSIONS

Results suggest that high levels of physical activity in acute AN associate with worst clinical conditions at admission, especially in terms of endocrinological and medical features.

LEVEL OF EVIDENCE

Level III.

Physical activity and sleep during the first week of anorexia nervosa inpatient care

Background

Individuals with Anorexia Nervosa are often described as restless, hyperactive and having disturbed sleep. The result reproducibility and generalisability of these results are low due to the use of unreliable methods, different measurement methods and outcome measures. A reliable method to measure both physical activity and sleep is through accelerometry. The main purpose of the study was to quantify the physical activity and sleeping behaviour of anorexia nervosa patients. Another purpose was to increase result reproducibility and generalisability of the study.

Material and methods

Accelerometer data were collected from the first week of treatment of anorexia nervosa at an inpatient ward. Raw data from the Axivity AX3^© accelerometer was used with the open-source package GGIR for analysis, in the free statistical software R. Accelerometer measurements were transformed into euclidean norm minus one with negative values rounded to zero (ENMO). Physical activity measurements of interest were 24h average ENMO, daytime average ENMO, inactivity, light activity, moderate activity, and vigorous activity. Sleep parameters of interest were sleep duration, sleep efficiency, awakenings, and wake after sleep onset. The sleep duration of different age groups was compared to recommendations by the National Sleep Foundation using a Fisher’s exact test.

Results

Of 67 patients, due to data quality 58 (93% female) were included in the analysis. Average age of participants was 17.8 (±6.9) years and body mass index was 15.5 (±1.9) kg/m². Daytime average ENMO was 17.4 (±5.1) mg. Participants spent 862.6 (±66.2) min per day inactive, 88.4 (±22.6) min with light activities, 25.8 (±16.7) min with moderate activities and 0.5 (±1.8) min with vigorous activities. Participants slept for 461.0 (±68.4) min, waking up 1.45 (±1.25) times per night for 54.6 (±35.8) min, having an average sleep quality of 0.88 (±0.10). 31% of participants met sleep recommendations, with a significantly higher number of 6–13 year old patients failing to reach recommendations compared to 14–25 year old patients.

Conclusion

The patient group spent most of their time inactive at the beginning of treatment. Most patients failed to reach sleep recommendations. The use of raw data and opensource software should ensure result reproducibility, enable comparison across points in treatment and comparison with healthy individuals.

Resting energy expenditure in acutely ill and stabilized patients with anorexia nervosa and bulimia nervosa

OBJECTIVE

Determining resting energy expenditure (REE) may be important in the nutritional assessment of adolescents with eating disorders (EDs). Calculated equations assessing REE, developed according to data from healthy people, may under- or overestimate REE in EDs. We have sought to compare the REE measured in clinical settings to that calculated using equations in actively ill adolescents with anorexia nervosa (AN) and bulimia nervosa (BN), and following stabilization of weight and disordered eating.

METHODS

Thirty-five female adolescents with AN and 25 with BN were assessed at admission to inpatient treatment and at discharge. REE was measured using indirect calorimetry (DELTATRAC Metabolic Monitor). Expected REE was calculated using the Harris-Benedict equation.

RESULTS

An overestimation of expected versus measured REE was found for both patients with AN and BN, both at admission and discharge. Second, the differences between expected and measured REE were significantly less robust in BN versus AN. Third, REE before renourishing was lower in inpatients with AN versus BN. Fourth, the REE of patients with AN (both measured and expected) increased from admission to discharge, to a greater extent than expected solely from the increase in weight. The difference between admission and discharge expected and measured REE was significant also in patients with BN.

DISCUSSION

Our findings suggest that predicted and measured REE are different in both AN and BN, and that both expected and measured REE are not useful in the planning of renourishing programs in patients with AN.

Physical Activity in Eating Disorders: A Systematic Review

Abnormally high levels of physical activity have been documented throughout the literature in patients with eating disorders (ED), especially those diagnosed with anorexia nervosa (AN). Yet no clear definition, conceptualization, or treatment of the problematic use of physical activity (PPA) in ED patients exists. The aim of this review is to propose a new classification of PPA, report the prevalence, triggers, predictors, maintainers and other related factors of PPA in ED patients, in addition to proposing a comprehensive model of the development of PPA in AN. A total of 47 articles, retrieved from Medline and Web of Science, met the inclusion criteria and were included in the analysis. As a result, the new approach of PPA was divided into two groups (group 1 and group 2) according to the dimension (quantitative vs qualitative approach) of physical activity that was evaluated. The prevalence of PPA in ED was reported in 20 out of 47 studies, the comparison of PPA between ED versus controls in 21 articles, and the links between PPA and psychological factors in ED in 26 articles, including depression (16/26), anxiety (13/26), obsessive–compulsiveness (9/26), self-esteem (4/26), addictiveness (1/26), regulation and verbal expression of emotions (1/26) and anhedonia (1/26). The links between PPA and ED symptomatology, PPA and weight, body mass index (BMI) and body composition in ED, PPA and age, onset, illness duration and lifetime activity status in ED, PPA and ED treatment outcome were reported in 18, 15, 7, 5 articles, respectively. All of the factors have been systematically clustered into group 1 and group 2. Results focused more on AN rather than BN due to the limited studies on the latter. Additionally, a model for the development of PPA in AN patients was proposed, encompassing five periods evolving into three clinical stages. Thus, two very opposite components of PPA in AN were suggested: voluntarily PPA increased in AN was viewed as a conscious strategy to maximize weight loss, while involuntarily PPA increased proportionally with weight-loss, indicating that exercise might be under the control of a subconscious biological drive and involuntary cognition.

Exercise Obsession and Compulsion in Adults With Longstanding Eating Disorders: Validation of the Norwegian Version of the Compulsive Exercise Test

Objectives

The objectives of this study were to (1) validate the Norwegian version of the Compulsive Exercise Test (CET) in adults with longstanding eating disorders, and (2) explore predictors of high CET-score.

Methods:

Adult inpatients (n = 166) with longstanding DSM-IV Anorexia Nervosa, Bulimia Nervosa (BN) or Eating Disorder not Otherwise Specified (EDNOS) completed the CET instrument, Eating Disorder examination questionnaire (EDE-Q), Beck Depression Inventory-II (BDI-II) and Symptom checklist-90 (SCL-90). A total CET score of 15 or above was defined as high CET-score. ANOVA, Confirmatory factor analysis, Pearson’s correlation, and logistic regression were used to analyze the data.

Results

Cronbach’s alpha varied from 0.68 to 0.96 for the CET and its subscales. The confirmatory factor analysis showed adequate fit. Convergent validity of the CET demonstrated correlation between EDE-Q global and subscale scores and CET total score. The same pattern was found for correlation between CET subscales and EDE-Q subscales. EDE-Q global score and frequency of exercise episodes predicted high CET-score, yet 21% of the patients with high CET score had less than one episode of exercise per week.

Conclusion

The Norwegian version of CET is valid and useful for assessing compulsive exercise in a sample with longstanding ED. The understanding of compulsive exercise must to a greater extent differ between obsessions and compulsions, as a significant number of patients with high CET score showed no or little exercise behavior.

Accuracy of self-reported physical activity in patients with anorexia nervosa: links with clinical features

BACKGROUND

High levels of physical activity (PA) have long been described in patients with Anorexia Nervosa (AN). Despite the importance of measuring PA in this population, there are two important factors that remain unknown. First, it is not clear how accurate self-report measures of PA are among patients. Second, little is known about how clinical characteristics are associated with the accuracy of self-reported PA. Therefore, this study aimed to examine the accuracy of self-reported PA compared to an objective measure of PA in patients with AN. It also investigated whether levels of accuracy/inaccuracy were associated with compulsive exercise, motivation to change, and psychological distress.

METHOD

Data were analysed from 34 adult outpatients with AN. Patients wore an accelerometer device (ActiGraph) for 4 days and completed a retrospective self-report measure of exercise (Exercise Participation Screening Questionnaire). They also completed measures of compulsive exercise (Compulsive Exercise Test), motivation to change (The Anorexia Nervosa Stages of Change Questionnaire), and psychological distress (Kessler-10).

RESULTS

On the self-report measure, patients accurately reported their time spent in moderate and vigorous intensity PA, however, they significantly under-reported their light physical activity (compared to the accelerometer data). Accurate reporting of total PA was positively associated with higher levels of compulsive exercise. There was evidence to suggest that clinical features, such as motivation to change and psychological distress, may be associated with inaccurate reporting at some levels of PA intensity and not others.

CONCLUSIONS

Results indicate that patients with AN are likely to under-report their light intensity PA. We also found preliminary evidence for how compulsive exercise, motivation to change, and distress are associated with self-reported PA accuracy. Clinical implications and directions for future research are considered.

TRIAL REGISTRATION

ACTRN12610000585022. Taking a LEAP forward in the treatment of anorexia nervosa: a randomized controlled trial. NHMRC grant: 634922.

High-intensity exercise is associated with a better nutritional status in anorexia nervosa

OBJECTIVE

Our aim is to investigate the links between duration and intensity of exercise and the nutritional status in terms of body composition in acute anorexia nervosa (AN) patients.

METHOD

One hundred ninety-one hospitalized women suffering from AN were included. Exercise duration and intensity were assessed using a semistructured questionnaire. Body composition was measured using bioelectrical impedance. Linear multiple regression analyses were carried out using body mass index, fat-free mass index, and fat mass index as dependent variables and including systematically exercise duration, exercise intensity, and other confounding variables described in the literature that were significantly associated with each dependent variable in univariate analysis.

RESULTS

A lower BMI was linked to lower exercise intensity, AN restrictive type, and presence of amenorrhea. A lower FFMI was linked to lower exercise intensity, older age, AN restrictive type, and premenarchal AN. Duration of exercise was not linked to the nutritional status.

CONCLUSIONS

Exercising at higher intensity in AN is associated with a better nutritional status, thus, a better resistance to starvation. The impact of therapeutic physical activity sessions, adapted in terms of exercise intensity and patient's clinical status, should be evaluated during nutrition rehabilitation.

Not the Function of Eating, but Spontaneous Activity and Energy Expenditure, Reflected in "Restlessness" and a "Drive for Activity" Appear to Be Dysregulated in Anorexia Nervosa: Treatment Implications

Anorexia nervosa (AN) is uncommon as a syndrome, despite widespread dieting or voluntary food restriction, especially among female adolescents. This suggests that restriction of caloric intake might not be the only component driving weight loss in AN. Historical observations and experimental evidence from energy expenditure studies and recordings from movement sensors reviewed in this paper reveal that AN is associated with motor activity levels and with an energy output not significantly different from that in normal-weight healthy age-matched controls. By contrast, other conditions of prolonged caloric under-nutrition are typically associated with loss of energy, slowing of movements and a decrease in self-initiated activity and well-being. Several hypotheses can be inferred from the findings: (a) that long term severe caloric restriction fails in downregulating movements and energy expenditure in AN. (b) Clinically and subjectively observable as mental and physical restlessness and continued motor activity, this restless energy, differing in intensity, seems to serve as the permissive factor for and possibly to drive exercise and hyperactivity in AN. (c) Such restless energy and increased arousal, generated sometime in the course of the weight loss process, appear to enhance the person's self-perception and wellbeing, to heighten proprioception, to intensify body awareness and to improve self-esteem. (d) Restlessness and continued motor activity may constitute a phenotype of AN. The therapeutic value of the concept of an abnormality in the energy regulatory system, likely the result of a host of genetic and epigenetic changes in AN, lies primarily in its heuristic and explanatory power and its potential for disease prevention. Restless energy as a permissive and important component for the development and in the maintenance of AN, does not fundamentally alter treatment, since prolonged food deprivation is the principal causal factor for the development of AN. Re-nutrition within a structured treatment plan, to include individual and family therapy and, if indicated, heat application, remains the most effective symptomatic treatment for AN. Corroboration of the concept of restless activation will require the patient's cooperation and input to identify and capture more precisely the experiences, sensations, and changes that allow the emaciated patient to remain mobile and active.

High Levels of Physical Activity in Anorexia Nervosa: A Systematic Review

High level physical activity is a frequent symptom in patients with anorexia nervosa (AN), influencing the development, maintenance, complications, treatment success, relapse rate and severity of the disease. Accelerometry is assumed to be an objective method to assess physical activity (PA) in AN. We aimed to review objectively measured levels of PA in AN and to give an overview for clinical practice and future research. Data were searched in PubMed and PsychINFO until April 2015 following the preferred reporting items for systematic reviews and meta-analyses statement. Twenty studies fulfilled the inclusion criteria. A notable heterogeneity of measurements, outcomes, participants and settings was found. Overall, HLPA is not adressed enough by current evidence. A common valid terminology of HLPA is not available, and accurate criteria of different levels of PA must be defined to create comparability of future studies. Further objective PA assessments are needed to improve treatment outcome and relapse rate.

Nutritional adequacy of dietary intake in women with anorexia nervosa

Understanding nutrient intake of anorexia nervosa (AN) patients is essential for the treatment. Therefore, estimates of total energy and nutrient consumption were made in a group of young women (19 to 30 years) with restricting and binge purge subtypes of AN participating in an ecological momentary assessment study. Participants completed three nonconsecutive 24-hour diet recalls. Mean nutrient intakes were stratified by subtype and by quartiles of energy intake and compared to the age specific Dietary Reference Intake (DRI) levels, as well as to the reported intakes from the What We Eat In America (WWEIA) dietary survey 2011–2012. Reported intake was determined for energy, macronutrients, and micronutrients. The mean body mass index (BMI) for all participants was 17.2 ± 0.1 kg/m². Reported nutrient intake was insufficient for participants in quartiles 1–3 of both AN subtypes when compared to the DRIs. Intake reported by participants in quartile 4 of both subgroups met requirements for most nutrients and even met or exceeded estimated energy needs. Counseling of AN patients should be directed to total food consumption to improve energy intake and to reduce individual nutritional gaps.

Counterregulation of insulin by leptin as key component of autonomic regulation of body weight

A re-examination of the mechanism controlling eating, locomotion, and metabolism prompts formulation of a new explanatory model containing five features: a coordinating joint role of the (1) autonomic nervous system (ANS); (2) the suprachiasmatic (SCN) master clock in counterbalancing parasympathetic digestive and absorptive functions and feeding with sympathetic locomotor and thermogenic energy expenditure within a circadian framework; (3) interaction of the ANS/SCN command with brain substrates of reward encompassing dopaminergic projections to ventral striatum and limbic and cortical forebrain. These drive the nonhomeostatic feeding and locomotor motivated behaviors in interaction with circulating ghrelin and lateral hypothalamic neurons signaling through melanin concentrating hormone and orexin-hypocretin peptides; (4) counterregulation of insulin by leptin of both gastric and adipose tissue origin through: potentiation by leptin of cholecystokinin-mediated satiation, inhibition of insulin secretion, suppression of insulin lipogenesis by leptin lipolysis, and modulation of peripheral tissue and brain sensitivity to insulin action. Thus weight-loss induced hypoleptimia raises insulin sensitivity and promotes its parasympathetic anabolic actions while obesity-induced hyperleptinemia supresses insulin lipogenic action; and (5) inhibition by leptin of bone mineral accrual suggesting that leptin may contribute to the maintenance of stability of skeletal, lean-body, as well as adipose tissue masses.

Metabolic dysfunction in anorexia nervosa

SUMMARY

CONTEXT

Anorexia nervosa (AN) is an eating disorder characterized by self-induced energy deficit and low body weight with major consequences for most organ systems and a tendency towards self-perpetuation.

OBJECTIVES

To compare metabolic responses to glucose and exercise in women hospitalized with AN (n = 10) before and after 6-weeks weight gain program and in lean healthy weight women (BMI < 22 kg/m(2)) (n = 7).

MAIN OUTCOMES

Weight, body composition, indirect calorimetry, and response of serum insulin, glucose, adiponectin and leptin to oral glucose (75 g) and to 30-min of cycling at 50 rpm.

RESULTS

Patients with AN had similar lean mass to controls, but had significantly less body fat. Adiponectin was 43% higher (p < 0.01) and leptin 47% lower in AN subjects versus controls (p = 0.04). In response to moderate exercise, fasting glucose increased in AN (p < 0.05), but was unchanged in controls. After glucose ingestion, a trend towards a greater increase in diet-induced thermogenesis was also observed in patients with AN (p = 0.07). Despite a further 6 weeks as in patients, weight was not significantly changed in AN. Similarly, glucose, insulin, leptin or adiponectin were not altered.

CONCLUSIONS

AN patients appear metabolically healthy under resting conditions, but their responses to physiological stressors differed from those of controls. Potential impediments to weight gain should be further investigated to define mechanisms with a view to improving the effectiveness of nutritional management.

Impact of exercise on energy metabolism in anorexia nervosa

BACKGROUND

Excessive physical activity is one of the most paradoxical features of anorexia nervosa (AN). However, there is individual variation in the degree of physical activity found in AN-patients. As a result, marked differences in energy expenditure may be expected. Furthermore, exercise has a positive impact on a variety of psychological disorders and the psychopathology may be different in AN displaying high exercise levels versus AN displaying low exercise levels. We analyzed the energy metabolism and psychological data in low-level exercise and high-level exercise AN-patients compared with healthy, age matched controls.

RESULTS

REE was decreased in AN-patients compared with controls but not when adjusted for body surface area or lean body mass. No differences in TDEE between AN- patients and controls were observed. Subgroup analyses showed that the percentage of high-level AN- exercisers was higher compared with controls. This subgroup had increased resting EE, total daily EE and scored higher on depression and the EDI-item "Drive for thinness" compared with low-level AN-exercisers.

CONCLUSIONS

We identified a significant subgroup of high-level AN-exercisers (66%) with consecutive increased energy requirements. An easy way for clinicians to assess the amount of exercise before and in the course of treatment is a single question in the established Eating Disorder Inventory-SC (EDI-SC).

Increased physical activity not decreased energy intake is associated with inpatient medical treatment for anorexia nervosa in adolescent females

There is a dearth of data regarding changes in dietary intake and physical activity over time that lead to inpatient medical treatment for anorexia nervosa (AN). Without such data, more effective nutritional therapies for patients cannot be devised. This study was undertaken to describe changes in diet and physical activity that precede inpatient medical hospitalization for AN in female adolescents. This data can be used to understand factors contributing to medical instability in AN, and may advance rodent models of AN to investigate novel weight restoration strategies. It was hypothesized that hospitalization for AN would be associated with progressive energy restriction and increased physical activity over time. 20 females, 11–19 years (14.3±1.8 years), with restricting type AN, completed retrospective, self-report questionnaires to assess dietary intake and physical activity over the 6 month period prior to inpatient admission (food frequency questionnaire, Pediatric physical activity recall) and 1 week prior (24 hour food recall, modifiable activity questionnaire). Physical activity increased acutely prior to inpatient admission without any change in energy or macronutrient intake. However, there were significant changes in reported micronutrient intake causing inadequate intake of Vitamin A, Vitamin D, and pantothenic acid at 1 week versus high, potentially harmful, intake of Vitamin A over 6 months prior to admission. Subject report of significantly increased physical activity, not decreased energy intake, were associated with medical hospitalization for AN. Physical activity and Vitamin A and D intake should be carefully monitored following initial AN diagnosis, as markers of disease progression as to potentially minimize the risk of medical instability.

Animal models of eating disorders

Feeding is a fundamental process for basic survival and is influenced by genetics and environmental stressors. Recent advances in our understanding of behavioral genetics have provided a profound insight on several components regulating eating patterns. However, our understanding of eating disorders, such as anorexia nervosa, bulimia nervosa, and binge eating, is still poor. The animal model is an essential tool in the investigation of eating behaviors and their pathological forms, yet development of an appropriate animal model for eating disorders still remains challenging due to our limited knowledge and some of the more ambiguous clinical diagnostic measures. Therefore, this review will serve to focus on the basic clinical features of eating disorders and the current advances in animal models of eating disorders.

Relevance of animal models to human eating disorders and obesity

BACKGROUND AND RATIONALE

This review addresses the role animal models play in contributing to our knowledge about the eating disorders anorexia nervosa (AN) and bulimia nervosa (BN) and obesity.

OBJECTIVES

Explore the usefulness of animal models in complex biobehavioral familial conditions, such as AN, BN, and obesity, that involve interactions among genetic, physiologic, psychological, and cultural factors.

RESULTS AND CONCLUSIONS

The most promising animal model to mimic AN is the activity-based anorexia rodent model leading to pathological weight loss. The paradigm incorporates reward elements of the drive for activity in the presence of an appetite and allows the use of genetically modified animals. For BN, the sham-feeding preparation in rodents equipped with a gastric fistula appears to be best suited to reproduce the postprandial emesis and the defects in satiety. Animal models that incorporate genes linked to behavior and mood may clarify biobehavioral processes underlying AN and BN. By contrast, a relative abundance of animal models has contributed to our understanding of human obesity. Both environmental and genetic determinants of obesity have been modeled in rodents. Here, we consider single gene mutant obesity models, along with models of obesigenic environmental conditions. The contributions of animal models to obesity research are illustrated by their utility for identifying genes linked to human obesity, for elucidating the pathways that regulate body weight and for the identification of potential therapeutic targets. The utility of these models may be further improved by exploring the impact of experimental manipulations on the behavioral determinants of energy balance.

Measurement of daily activity in restrictive type anorexia nervosa

OBJECTIVE

The assessment of daily activity in patients with restrictive type anorexia nervosa is limited by an absence of accurate and precise technology. We wanted to test a daily activity detecting device named, the physical activity monitoring system (PAMS).

METHOD

Women participants with restrictive type anorexia nervosa (n = 8, 36 +/- 11 years, 17 +/- 2 kg/m(2)) and healthy women participants (n = 8, 30 +/- 11 years, 27 +/- 7 kg/m(2)) were asked to lie, sit, and stand motionless, and walk at 0.5, 1.0, 1.5, 2.0, 2.5, and 3.0 mph while wearing PAMS.

RESULTS

For all restrictive type anorexia nervosa and healthy participants, body posture was correctly detected for all measurements (300/300). There was excellent correlation of an individual's body acceleration with walking velocity and walking energy expenditure (r(2) > .99).

CONCLUSION

The PAMS technology could serve as a tool for lending insight into the pathophysiology of restrictive type anorexia nervosa; and potentially measuring compliance with activity recommendations for medical professionals treating individuals with restrictive type anorexia nervosa.

How accurate are predictive formulas calculating energy expenditure in adolescent patients with anorexia nervosa?

BACKGROUND & AIMS

To compare resting energy expenditure, measured by indirect calorimetry, to values estimated by different predictive formulas in adolescent patients with anorexia nervosa.

METHODS

We studied 22 female in-patients with a mean age of 14.7 years (SD 1.2). Resting energy expenditure was measured by indirect calorimetry (Deltatrac II MBM-200). We compared measured resting energy expenditure to values estimated by several predictive formulas [Fleisch, Harris-Benedict, FAO, Schofield-HW, Schebendach] using the intraclass correlation coefficient and the Bland-Altman method.

RESULTS

Body mass index increased significantly (P<0.001). Measured resting energy expenditure increased during hospitalization (P<0.05). All formulas overestimated resting energy expenditure with respect to indirect calorimetry except the Schebendach formula. The intraclass correlation between indirect calorimetry and the formulas were poor (0.09-0.20). We observed a poor clinical agreement (Bland-Altman).

CONCLUSIONS

Body mass index and resting energy expenditure increased during hospitalization. The majority of the predictive formulas overestimate resting energy expenditure in adolescent patients with anorexia nervosa. Therefore, indirect calorimetry may be a very useful tool for calculating caloric requirements in these patients.

The 'drive for activity' and "restlessness" in anorexia nervosa: potential pathways

This paper discusses the hypothesis that a 'drive for activity" in the presence of physiological and endocrine changes consistent with starvation is a characteristic symptom of acute anorexia nervosa (AN). This 'drive for movement', along with alertness and lack of fatigue, so unlike the motor slowing and loss of energy observed in simple starvation has been recognized in AN throughout history, but has received little attention in the past fifty years. Clinical reports and experimental evidence suggest that 'restlessness' and a 'drive for activity' vary in intensity, they appears to be starvation-dependent and to wane with food intake. Central nervous system (CNS) systems known to be involved in mediating activity and arousal levels that are altered by the negative energy expenditure in AN are reviewed. Among these, the corticotropin-releasing hormone (CRH) system, the melanocyte stimulating hormone/agouti-related protein (MSH/AGRP) system and the norepinephrine/epinephrine (NE/EPI) and dopamine (DA) system may contribute to the 'drive for activity' and alertness in AN. AN appears to represent a disorder of gene/environment interaction. Future research will reveal whether in individuals predisposed to AN, the 'drive for activity' reflects the reactivation of mechanisms important in food scarcity, controlled by one or more evolutionary conserved genes including those regulating foraging behavior. Recognition of the 'drive for activity' as a diagnostic symptom of AN and its assessment prior to re-nutrition would permit clarification of its role in the etiology of AN.

The usefulness of experience sampling in understanding the urge to move in anorexia nervosa

BACKGROUND

Physical hyperactivity has often been described in anorexia nervosa (AN) patients but up until now in-depth research has been scarce. Experience sampling methodology (ESM), a structured diary technique assessing momentary mental state at random times during the day, may be useful in studying hyperactivity in AN.

METHODS

In two single case reports, ESM was used to investigate the variation across time of the urge to move in relation to potentially relevant eliciting conditions such as positive and negative emotions, weight preoccupation and attractiveness.

RESULTS

Frequency distribution of the involved variables indicated substantial individual differences between patients. While both patients' tendency to be hyperactive was positively related to their weight preoccupation and negative emotions, in only one patient, the urge to move turned out to be significantly related to (the absence of) positive emotions.

CONCLUSIONS

ESM can be useful to test whether general theories of psychopathology apply to specific patients, and it may be conceived as an individually tailored approach to self-monitoring. As such, it may guide the clinician to devise therapeutic interventions in particular patients.

Effects of binge eating behavior on fuel oxidation and body composition

OBJECTIVE

To investigate energy expenditure and glucose metabolism after a standard oral glucose load (75 g) in 8 normal weight bulimic women and 8 normal weight control women and to evaluate the relative endocrine implication.

DESIGN

Serum glucose and insulin were measured both in basal conditions and after the glucose load; a basal endocrine assessment and body composition was evaluated and glucose induced thermogenesis (GIT) was calculated during 300 min following the glucose load.

RESULTS

Serum glucose levels were significantly lower in bulimics both in fasting and in post-prandial state. Insulin levels were similar in bulimic and control women before and after the glucose load. FSH, leptin and free urinary cortisol (FUC) were all within the normal ranges, but significantly lower in bulimic patients compared with controls (p < 0.001). Fat mass (FM) and Fat-free mass (FFM) were reduced in bulimic patients, even if they normalized after correction per body weight. Resting energy expenditure (REE) was similar in the two groups even after FFM normalization, while GIT was lower in bulimic patients and it was strongly related to free urinary chortisol. Glucose oxidation was higher in fasting state and post glucose load, while lipid oxidation was strongly reduced.

CONCLUSION

An energy preservation mechanism seems to be the key element for normal-weight bulimic patients' metabolism, consisting in leptin levels and GIT reduction, and lipid oxidation inhibition.

Energy and macronutrient intake in bulimia nervosa

Energy deprivation and malnutrition are often thought to be key factors in the maintenance of bulimia nervosa (BN). Our review shows that it is unclear how much energy is actually available to BN patients' metabolism because the contribution of food consumed during binge eating is generally neglected. Also, there is little evidence for another key hypothesis that binge-eating episodes are triggered by carbohydrate craving. This study examined energy consumption and macronutrient composition of meals and binge-eating episodes in food diaries. Forty female BN patients, 40 female panic disorder (PD) patients, and 40 healthy women recorded their food intake while in their natural environment during two consecutive days. We did not find the expected evidence for chronic energy deprivation and malnutrition in BN patients. Also, there was no evidence that carbohydrate craving drives binge eating. The implications for models of BN and for treatments targeting eating behavior are discussed.

Hyperactivity in patients with anorexia nervosa and in semistarved rats: evidence for a pivotal role of hypoleptinemia

Patients with anorexia nervosa (AN) often show normal to elevated physical activity levels despite severe weight loss and emaciation. This is seemingly in contrast to the loss of energy and fatigue characteristic of other starvation states associated with weight loss. Despite the fact that historical accounts and clinical case studies of AN have regularly commented on the elevated activity levels, the behavior has become only recently the subject of systematic study. Because rodents and other species increase their activity upon food restriction leading to weight loss when given access to an activity wheel--a phenomenon referred to as activity-based anorexia or semi-starvation-induced hyperactivity (SIH)-it has been proposed that the hyperactivity in AN patients may reflect the mobilization of phylogenetically old pathways in individuals predisposed to AN. Exogeneous application of leptin in this animal model of AN has recently been shown to suppress completely the development of SIH. Hypoleptinemia, as a result of the food restriction, may represent the initial trigger for the increased activity levels in AN patients and in food-restricted rats. In the first and second parts of our review, we will summarize the relevant findings pertaining to hyperactivity in AN patients and in the rat model, respectively. We conclude with a synopsis and implications for future research.

Research on energy expenditure in individuals with eating disorders: a review

OBJECTIVE

This study reviews the published research on energy expenditure in individuals with anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED).

METHOD

Individual studies are reviewed and their results summarized.

RESULTS

The most consistent finding is a reduction in resting energy expenditure (REE) in patients with AN, which increases with increased energy intake and body weight. Data regarding BN are inconsistent. Three available studies in subjects with BED have not found evidence of changes in energy expenditure corrected for lean body mass compared with obese non-binge eaters.

DISCUSSION

The ability to measure REE reliably and cost-effectively may aid in the refeeding of patients with AN in whom REE is reduced. Changes in individuals with BN and BED have yet to be consistently identified.

Research on energy expenditure in individuals with eating disorders: a review

OBJECTIVE

This study reviews the published research on energy expenditure in individuals with anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED).

METHOD

Individual studies are reviewed and their results summarized.

RESULTS

The most consistent finding is evidence of reduction in resting energy expenditure (REE) in patients with AN, which increases with increased energy intake and body weight. Data regarding BN are inconsistent. Three available studies in subjects with BED have not found evidence of changes in energy expenditure corrected for lean body mass compared with obese non-binge eaters.

DISCUSSION

The ability to reliably and cost-effectively measure REE may aid in the refeeding of patients with AN where REE is reduced. Changes in BN and BED subjects have yet to be identified consistently.

Total energy expenditure as measured by doubly-labeled water in outpatients with bulimia nervosa

OBJECTIVE

This study measured total energy expenditure (TEE) in symptomatic outpatient women with bulimia nervosa and normal controls. The study aimed to test the conceptual model of bulimia nervosa as an illness characterized by a physiological state of starvation, despite normal weight.

METHOD

Total fat and fat-free mass were measured using hydrodensitometry and total energy expenditure was assessed via the doubly-labeled water method, in nine normal weight outpatient females with DSM-III-R bulimia nervosa and ten healthy female controls.

RESULTS

Patients and controls were similar in age, body mass index, weight, lean body mass, and levels of exercise and general activity. Patients had an average baseline binge frequency of 14.7 episodes per week and purge frequency of 16.8 times per week, and had been ill for an average of 11.9 years. Group mean TEE did not differ between patients and controls (patients 2380 +/- 482 kcal/day, controls 2368 +/- 515 kcal day). Observed TEE in the bulimic subjects did not differ significantly from TEE predicted on the basis of data from the controls.

DISCUSSION

This finding of normal TEE in symptomatic outpatients with bulimia nervosa is consistent with a previous study that found no difference in TEE in a sample of symptomatic inpatients with bulimia nervosa. These data suggest that the energy conserving metabolic adaptations characteristic of semi-starvation do not occur in patients with bulimia nervosa.

Altered energy metabolism in anorexia nervosa

Optimal nutritional rehabilitation of anorexia nervosa requires more information concerning actual energy and substrate requirements. To this end, indirect calorimetry was performed in female patients (n=34, age 20.9+/-1.2 yr, body mass index [BMI] 15.6+/-0.2 kg/m(2); mean+/-SEM) soon after commencement of refeeding and at the time of discharge from hospital (n=18, BMI 19.0+/-0.3 kg/m(2)). Healthy female controls (n=18, age 24.6+/-1.3 yr, BMI 21.6+/-0.6 kg/m(2)) were also tested. Resting energy expenditure (REE) and respiratory quotient (RQ) were measured in the fasting state, followed by diet-induced thermogenesis (DIT) and RQ over a 4 h period following a 100 g oral glucose load. Compared with post-refeeding patients and controls, pre-refeeding patients had a high basal RQ and a low REE, with a paradoxically higher DIT (13.2+/-0.9% of REE vs. 8.3+/-1.2% and 8.6+/-0.9% in post-refeeding patients and controls, respectively). RQ values in pre-refeeding patients exceeded unity following the glucose load, probably reflecting net lipogenesis, whereas in the post-refeeding patients, post-glucose RQ was similar to that of controls, suggesting premature curtailment of lipogenesis. These data demonstrate energy wasting in emaciated patients with anorexia nervosa. Biological repair processes could account for disproportionate energy loss early in refeeding and there may be some later impediment to full restoration of fat stores.

The metabolic responses to starvation and refeeding in adolescents with anorexia nervosa

Adaptive changes in metabolism result in decreased energy requirements in AN. A retrospective study of 21 hospitalized female AN patients demonstrated that indirect calorimetry (IC) measurement of resting energy expenditure (REE) was significantly lower than REE calculated by the Harris-Benedict equation (HBE). The HBE was adjusted by multiple-regression analysis to reflect the hypometabolic state of AN, and the adjusted equation was prospectively validated in 37 hospitalized female AN patients. Refeeding requires an understanding of both baseline requirements and metabolic changes that occur during nutritional rehabilitation. In our present study, we prospectively evaluated changes in fasting and postprandial REE in 50 hospitalized female patients meeting DSM-IV criteria for AN. Baseline IC measurements of fasting and postprandial REE were obtained within three days of admission, and every two weeks thereafter. Mean fasting REE increased significantly from 72 (+/-11.7) to 83.2 (+/-12.6) percent of predicted (p < 0.001) during the first two weeks of hospitalization. Likewise, postprandial REE also increased significantly from 17.5 (+/-18.2) to 27.9 (+/-15.9) percent above fasting REE during the same time period (p < 0.01). Significant increases in both REE and postprandial REE persisted in patients requiring longer hospitalizations. Despite the fact that prescribed energy intake and triiodothyronine (T3-RIA) levels increased during refeeding, there was no significant relationship between postprandial REE and energy intake or T3 levels after baseline. We conclude that energy metabolism in AN adapts to semistarvation by a reduction in fasting REE. With refeeding there is a reversal of this adaptive function, demonstrated by an increase in both fasting and postprandial energy expenditure. The increase in postprandial REE is not related to energy intake or thyroid function.

Nutritional management of eating disorders

Abnormal nutritional status and dietary patterns are central features of the eating disorders. Normalization of these features are key components of treatment and recovery because they are powerful perpetuating factors. Restrictive diets, fat avoidance, and abnormal cognitive and perceptual patterns are typically present, in addition to altered nutritional parameters because of hormonal and metabolic factors. The primary goal of nutrition intervention in the patient with anorexia nervosa is to promote weight gain through increased energy intake, expansion of the diet, and knowledgeable and empathetic dietary counseling. A regular pattern of nutritionally balanced, planned meals and snacks, and the avoidance of restrictive dieting, are essential elements of treatment for the patient with bulimia nervosa. As a member of the multidisciplinary treatment team, the dietitian or nutrition professional with knowledge of nutritional science, counseling skills, and a nonjudgmental attitude can provide expertise in this area.

Body mass index and daily physical activity in anorexia nervosa

The level of daily physical activity in 11 non-hospitalized women with anorexia (age: 21-48 yr, body mass index (BMI): 12.5-18.3 kg.m-2), compared with 13 normal-weight women (age: 20-35 yr, BMI 19.2-26.7 kg.m-2), was studied in relation to BMI. Daily physical activity over a 7-d period was determined from movement registration and by combining measurements of average daily metabolic rate (measured in a respiration chamber). Group averages of daily physical activity were similar for subjects with anorexia and control subjects. However, women with anorexia had either a low or a high level of daily physical activity, whereas most control subjects had a moderate level of daily physical activity. In the women with anorexia, daily physical activity was significantly related to BMI (r = 0.84). Subjects with a BMI > or = kg.m-2 were equally or more active compared with control subjects, while subjects with a BMI < 17 kg.m-2 were equally or less active compared with control subjects. The increased physical activity at BMI > or = 17 kg.m-2 is considered to be facilitated by an improving physical capacity combined with the advantages of a low body mass during weight-bearing activities. At lower BMI, undereating and declining physical capacity may have caused the observed decrease in daily physical activity.

Resting metabolic rate and total energy expenditure in acute and weight recovered patients with anorexia nervosa and in healthy young women

Because little is known about energy requirements in anorectic patients before and after weight gain we measured resting metabolic rate (RMR) by indirect calorimetry and total energy expenditure (TEE) by the doubly labeled water method in 6 patients with anorexia nervosa (body mass index [BMI] = 15.1 +/- 1.3 kg/m2), in 6 weight-recovered anorectics (BMI = 21.2 +/- 2.1 kg/m2), and in 12 healthy age-matched women (BMI = 20.5 +/- 1.9 kg/m2). No significant differences were found between the weight-recovered anorectic women and the healthy controls in RMR (1,330 +/- 131 kcal/day [weight-recovered]; 1,419 +/- 197 [controls]) and in TEE (2,602 +/- 637 kcal/day [weight-recovered]; 2,596 +/- 493 kcal/day [controls]). The RMR was significantly lower in the acutely ill anorectic patients (1,171 +/- 113 kcal/24 hr) than in weight-recovered anorectics and in healthy controls. The TEE was significantly lower in the anorectic group (1,946 +/- 192 kcal/day) than in the healthy controls.

Nutritional disorder of anorexia nervosa: a review

In the treatment of anorexia nervosa, the importance of weight restoration has been well documented. Resting energy expenditure, which is initially reduced, often increases markedly in association with refeeding. Previous studies that have examined micronutrient status in anorexia nervosa have reported inconsistent and sometimes contradictory conclusions, due to the heterogeneity of the population, the cross-sectional nature of these investigations, and, at times, the use of inappropriate methods to determine nutrient status. Abnormal nutritional findings in patients with anorexia nervosa are primarily a consequence of semistarvation. Neuroendocrine abnormalities, degree of recovery, and phase of treatment affect interpretation of data. Despite the importance of nutritional rehabilitation, few controlled studies that address the clinical efficacy of various dietary treatment regimens have been conducted.

Starvation-induced hyperactivity in the rat: the role of endocrine and neurotransmitter changes

Semistarved rats develop high running wheel activity. This running activity induces increased norepinephrine, dopamine, and serotonin turnover in the hypothalamus. Corticosterone in plasma becomes increased while luteinizing hormone and testosterone are suppressed. In female rats cyclic gonadal function is suppressed. Running activity in the semistarved rats can be suppressed specifically by serotonin 1-c-agonists and by alpha 2-adrenoceptor agonists. This animal model is helpful in the understanding of the combined effects of starvation and hyperactivity, which are observed in many patients with anorexia nervosa. The observation of the serotonergic system might help to develop a pharmacological treatment of hyperactivity in anorectic patients.

Changes in resting energy expenditure and body composition in anorexia nervosa patients during refeeding

Accurate prediction of the energy level necessary to promote weight restoration in patients with anorexia nervosa would be clinically useful. Resting energy expenditure (REE), respiratory quotient, and body composition were measured in 10 nonmedicated women with anorexia nervosa during a vigorous refeeding protocol. REE was measured three times per week by open-circuit indirect calorimetry after an overnight fast. Subjects ranged in age from 19 to 38 years and weighed 39.9 +/- 4.3 kg (mean +/- standard deviation) at admission. The refeeding protocol was as follows: phase 1, 1,200 kcal/day for 1 week (baseline); phase 2, an increase of 300 kcal/day for 1 week; phase 3, 3,600 kcal/day until target weight was reached; phase 4, 1,800 to 2,800 kcal/day (stabilization). REE was 30.0 +/- 6.4, 33.5 +/- 6.7, 37.3 +/- 6.6 and 34.5 +/- 4.4 kcal/kg body weight during phases 1, 2, 3, and 4, respectively. The Harris-Benedict equation overestimated phase 1 24-hour REE by a mean of 14% and underestimated REE in phases 2, 3, and 4 by a mean of 8%, 24%, and 23%, respectively. Skinfold measurements revealed percent body fat to be 12 +/- 4% at admission and 19 +/- 5% at discharge, with a mean of 48% of the weight gained during refeeding attributable to increased body fat. These findings indicate that refeeding in anorexia nervosa is associated with increased REE, which cannot be explained by increased body mass, and that caloric requirements for weight restoration in patients with anorexia nervosa are best determined by monitoring individual response.