Factors related to required excess energy for weight gain in patients with anorexia nervosa under strict behavioral control: a study in a Japanese medical prison

doi:10.21203/rs.3.rs-5826267/v1

Background

This study aimed to establish the amount of excess calories required for a weight gain of 1 kg in the recovery period of patients with anorexia nervosa (AN) and to identify factors influencing weight gain.

Methods

Forty-one patients with AN in a Japanese medical prison were included in the study. All the data were collected from the medical charts. Body composition was measured using multifrequency bioelectrical impedance devices (InBody 770®) and body weight. Daily caloric intake was determined by calculating the amount of leftover food and resting energy expenditure was calculated using Scalfi's formulation. These were then used to calculate daily excess energy and excess energy for 1-kg weight gain (EE1). In addition, we investigated the relationship between EE1 and initial body composition values, body mass index, and AN subtype.

Results

Of the 41 patients, two had EE1s that we considered outliers. Excluding these, the mean EE1 was 12776.8 kcal/kg with large individual differences observed (range: 6636–22064 kcal/kg). Significant associations were noted between EE1 and body fat mass, body fat percentage, soft lean percentage, and body water ratio. Moreover, patients with BFM ≤ 3 kg (p = 0.003), BFP ≤ 8% (p = 0.008), SLP > 85% (p = 0.011), and BWR > 0.665 (p = 0.011) had higher mean EE1s.

Conclusions

Patients with AN may require more calories than healthy women, particularly patients with less fat and more muscle who may require a greater energy intake for weight gain. (234/350words)

anorexia nervosa

excess energy

weight gain

body composition

multifrequency bioelectrical impedance

Anorexia nervosa (AN) is a mental illness characterized by excessive calorie restriction and fear of weight gain that can be fatal. Calorie restriction leads to severe malnutrition and weight loss, which may cause other physical and mental comorbidities. Comorbidities may prolong and complicate the disease, making it more difficult to treat (1). Therefore, renourishment and weight recovery are the most important aspects of AN treatment.

While many aspects of refeeding in patients with AN have been elucidated, the number of calories required to gain weight remains unclear. The 2004 National Institute for Health and Care Excellence (NICE) guidelines recommended a weight gain of 0.5 kg to 1.0 kg per week, requiring approximately 3500 kcal to 7000 kcal extra calories per week(2). However, other reports have included a wide range of calories needed for a weight gain of 1 kg (3).

A higher calorie intake is required for an increase in weight of 1 kg in patients with AN than that required for the same weight increase in healthy women or patients with bulimia nervosa (6)(7)(8), despite the low body weight of patients with AN. This finding may be explained by changes in gut microbiota or function(4)(5), changes in endocrine function(9), elevated diet-induced thermogenesis (DIT)(10)(11) and hyperactivity, which is an AN-specific behavior. Although weight gain in patients with AN is important for recovery, the reported calories required for weight gain have been inconsistent. Furthermore, most previous reports have included study populations of 20 or fewer patients, which may not be sufficient for conclusive results.

Moreover, concerns regarding body shape and weight are important for patients with AN, increasing resistance to body shape and weight changes induced by refeeding. In our practice, we often encounter patients with an increased fear of obesity due to unexpected weight gain, who conceal vomiting or food wasting, even during inpatient treatment. In such cases, knowledge of the EE1 may allow patients to better cope with their fear of obesity, as they are aware of the prospect of weight gain. Therapists can also use the EE1 as a reference for prescribing patient re-nutrition and as guidance for deciding whether the patient's weight gain during re-nutrition is appropriate. Therefore, the ability to predict the amount of weight gain and possible body changes may facilitate recovery from AN. Furthermore, strict management of patient behavior in studies on energy intake for weight gain in patients with AN may also be required. Previous studies have been conducted in general hospital settings, where strictly managing patient behavior may have been difficult.

The present study aimed to investigate how many excess calories were required for a weight gain of 1 kg in the recovery period of patients with AN and to identify factors influencing weight gain. We hypothesized that the excess energy intake required to gain 1-kg body weight during the weight recovery period of patients with AN would be more than that required for healthy women. Additionally, we postulated that the excess energy required would be affected by pre-weight recovery body composition.

Participants

This study was a retrospective, observational study. Data were collected at Kitakyushu Medical Prison and analyzed at the Department of Psychosomatic Medicine, Kyushu University.

Forty-one female patients who were imprisoned and treated at Kitakyushu Medical Prison between February 2013 and July 2018 and diagnosed with AN according to the Diagnostic and Statistical Manual of Mental Disorders-5 were enrolled. Patients who had undergone their first anthropometric measurements more than 30 days after admission or who had experienced severe physical complications that caused them to lose weight for reasons other than AN, were excluded.

This study was approved by the Kitakyushu Medical Prison Ethics Review Committee and the Kyushu University Clinical Research Ethics Review Committee [22013-00]. The ethical aspects and the necessity of the study involving prisoners were reviewed by both ethics committees in accordance with the principles of the Declaration of Helsinki. All the data were collected from the medical charts of patients who were treated in the Kitakyushu Medical Prison. We were unable to contact the individuals after their release from prison to obtain direct consent. However, we announced the study on the bulletin board of Kitakyushu Medical Prison and on the website of the Department of Psychosomatic Medicine Graduate School of Medical Science Kyushu University and made it possible for the patients to refuse participation in the study. For these reasons, both ethics review committees waived the requirement for participant consent based on the retrospective study design and the anonymisation and de-identification of data.

Treatment

Initial treatment included renourishment and stabilization of patient condition. Patients were started on a diet of approximately 30 kcal/kg/day (at least 1000 kcal/day). We introduced a liquid nutritional supplement (100 kcal/day) containing phosphates and other trace elements to prevent refeeding syndrome for approximately 1 month (12)(13). The caloric intake provided did not exceed 2100 kcal/day, since an intake of 1800–2100 kcal/day is recommended for healthy Japanese women. Initially, patients were only allowed to lie down in their rooms until their eating habits and condition had stabilized. Patients received an amount of food they could eat completely without effort and liquid meals were added as supplements for those who were unable to eat adequate amounts to achieve the energy intake of 30kcal/kg/day. The use of nasogastric tubes or intravascular nutrition was rare. We did not define the timeframe for administering meals with a specific calorie content. We also did not prescribe increments in activity or food intake with time. If the patients could easily consume all the food provided, we increased the amount by 200 kcal. However, if patients could not finish a meal or experienced vomiting, we reduced their food intake and substituted it with a liquid meal to ensure adequate energy intake. We controlled these aspects to maintain weight gain until a healthy weight was obtained. Our psychobehavioral treatment is based on a "cognitive-behavioral approach with behavioral limitation." (12) This treatment incorporates the techniques of the operant conditioning therapy and cognitive behavioral therapy. The primary objective of this treatment is to facilitate the transformation of the patient's conventional coping behaviors, such as avoiding stressful situations and negative emotions through anorexia, overeating, and vomiting, into adaptive cognitive-behavioral patterns, thereby fostering mental growth. During initial imprisonment, participants were only allowed in their rooms as areas of activity. However, participants were allowed to expand their activities based on subsequent conditions, such as eating a complete meal, quitting vomiting or talking about introspection etc. Finally, they were allowed up to two hours of sedentary light work and 30 minutes of outside activity per day. During outside activities, most participants read or walked slowly and did not engage in strenuous exercise. We did not use activity meters during observations; therefore, we could not assess the exact amount of physical activity.

Particularly during the first half of the treatment, we emphasized the importance of patients being able to consume their meals completely and stop vomiting. As the treatment progressed, this behavioral limitation is gradually eased in response to appropriate eating behaviors and weight regain. This approach has been shown to be effective in increasing weight and enabling patients to engage in self-reflection (12). By eliminating the inappropriate avoidance behaviors previously adopted, the therapeutic structure allowed patients to confront their original negative emotions and emotional problems. In addition, patients attended sessions with an eating disorder specialist, involving psychological interviews, approximately once a week, and family interviews were held if considered necessary. Some patients who showed progress in their treatment and became capable of self-reflection were allowed to participate in group meetings.

Due to the nature of the medical prison facility, strict monitoring of the participants was in place, making self-induced vomiting as well as hiding or disposing of food nearly impossible. Except for work hours or outside activity hours, the participants were not allowed to leave their room without permission. Work and activities were monitored by prison officers. Furthermore, a monitoring camera was installed in their room, and they used a toilet, which they could not flush by themselves. Moreover, use of the water supply was monitored by prison officers and participants could not drink without permission.

Anthropometry

Body compositions were assessed with a multifrequency bioelectrical impedance analysis (BIA) device (InBody 770®; Biospace, Seoul, Korea). InBody 770® can measure body weight (BW), fat, soft lean, and water values and can distinguish between total, trunk, and limb values. Patient body composition and body weight were measured by the BIA device once a week from admission to week 6, once every two weeks in weeks 7–12, and once a month after week 13. Measurements were taken at 8:30 am with patients wearing their uniforms and checked by a nurse or prison officer.

Calculation of the excess energy required to gain weight

After each meal, the prison officer or nurse checked the amount of food left on the tray. Main and side dishes were categorized separately, after which the daily energy intake was calculated based on the remaining food. The energy provided via liquid meals or intravascular nutrition was also added to the daily energy intake for patients requiring liquid nutritional supplementation. Daily excess energy (EE) was calculated daily using the latest BW measured by a BIA device.

For excess energy calculations, we used the Scalfi’s formulation (14). The Scalfi’s formulation is used to calculate resting energy expenditure in women with AN. The "0.238" in the formulation is the number used to convert units from "kJ" to "kcal. To calculate excess energy, the activity factor was set at 1.3 because the participants were only doing sedentary work for up to 2 hours and light outdoor activities for up to 30 minutes per day. We calculated the excess energy as follows:

Scalfi’s formulation: resting energy expenditure (kcal / day) = 96.3 * BW (kg) * 0.238

Excess Energy (EE : kcal / day) = [Intake energy] – [Scalfi’s resting energy expenditure] * 1.3

In this study, we defined the period during which the patient maintains or decreases their body weight for more than 2 months as the “plateau period” and the period before the “plateau period” as the “weight gain period.” We used the weight gain period only to calculate the energy required to gain weight. We calculated a regression line using the amount of changing BW as the explanatory variable and the accumulated excess energy as the objective variable in each patient. The coefficient of the regression equation indicated the excess energy required to increase 1-kg BW (EE1), after which we calculated the average EE1.

Study of the factors for weight gain

We evaluated the relationship between the first measurements of body compositions, AN subtype, and BMI and EE1 by a scatter plot. Factors that showed correlations with EE1 were divided into two groups within the range of 25–75% quartiles and the values showing a difference between the groups were investigated.

Statistical analysis

To investigate the factors for weight gain, a one-way analysis of variance was used to compare EE1 with categorical variables (subtype). The relationship between EE1 and continuous variables (BMI and body composition) was analyzed using scatter plots and Pearson’s correlation coefficients. We used t-tests to compare EE1 with continuous variables (BMI and body composition) between groups, and p-values of < .05 were considered statistically significant. Additionally, correlation coefficients of 1>|r|≥0.7, 0.7 >|r|≥0.4, 0.4 >|r|≥ 0.2, and 0.2 >|r| indicated strong, moderate, weak, and no correlations, respectively. All statistical analyses were performed with JMP Pro Ver.14 (SAS Institute Inc.).

Clinical characteristics

A total of 64 patients with a diagnosis of AN were detained in the Kitakyushu Medical Prison between February 2013 and July 2018. Of these, 23 were excluded from the study because anthropometric measurements were first taken after more than 30 days of imprisonment. The baseline clinical characteristics of the patients enrolled and the changes in weight and BMI are presented in Table 1. <Table 1 insert here>

Table 1

Baseline characteristics and changes in the weight gain period
Subtype	AN-R	n = 10
	AN-BP	n = 31
Age			44.05 ± 8.38 (30–68)
Height (cm)			156.76 ± 6.44 (144.4–178.0)
Weight (kg)			32.22 ± 3.80 (25.9–40.4)
BMI (kg/m2)			13.12 ± 1.40 (9.9–15.8)
Total body water (L)			22.03 ± 2.64 (17.6–29.1)
Body water ratio			0.685 ± 0.037 (0.583–0.723)
ECW/TBW			0.394 ± 0.008 (0.376–0.407)
Body fat mass (kg)			2.30 ± 1.53 (0.8–6.2)
Body fat percentage (%)			7.04 ± 4.55 (3-20.4)
Soft lean mass (kg)			28.18 ± 3.41 (22.4–37.2)
Weight gain period (days)			302 ± 108 (97–531)
Weight change (kg)			14.94 ± 5.32 (2.5–24.5)
BMI change (kg/m2)			6.1 ± 2.2 (0.9–9.8)
Daily calorie intake(kcal/day)			1858 ± 278 (50-2560)
Final weight(kg)			47.2 ± 6.2 (33.9–57.1)
Final BMI(kg/㎡)			19.2 ± 2.5 (13.2–23.6)
Values are means ± SD (range). AN-R; anorexia nervosa-restricting type, AN-BP; anorexia nervosa-binge eating/purging type, BMI; body mass index, ECW; extracellular water, TBW; total body water

Three quarters of the patients were binge-eating/purging type (AN-BP) with a mean age of 44.05 ± 8.38 years which was higher than the typical mean age of AN. The average BW, BMI, and percentage of body fat was 32.22 ± 3.8 kg, 13.12 ± 1.40 kg/m², and 7.04 ± 4.55%, respectively. The weight restoration period was 302 days, which was longer than the length of a general hospital stay in Japan. Daily calorie intake of during period of weight restoration was almost the same as the energy needs of a healthy adult woman (1858 ± 278 kcal/day) (15).

During treatment, 38 patients gained more than 5 kg of BW, and 25 patients achieved BMIs > 18.5 kg/m² prior to leaving prison. However, one patient only gained 0.2 kg during the 651-day admission period.

Excess energy required to gain weight

In two out of 41 patients EE1 values were considered outliers as these were over three times the 75th percentile value. Excluding these outliers, the average EE1 was 12776.8 kcal/kg (SD: 3334.8), with large individual differences noted (range: 6636–22064 kcal/kg) and a coefficient of variation (CV) of 26.1%.

Factors for weight gain

The relationships between EE1 and the AN subtype as well as body composition were analyzed to elucidate factors that may cause weight gain. The relationships between EE1 and the AN subtype as well as the first measured value of BMI, fat mass (FM), body fat percentage (BFP), soft lean mass (SLM), soft lean percentage (SLP), and body water ratio (BWR: body water/body weight) are shown in Fig. 1. A significant correlation was observed between EE1 and FM (Fig. 1a), BFP (Fig. 1b), SLP (Fig. 1c), and BWR (Fig. 1d), while SLM (Fig. 1e) appeared to have no correlation with EE1. Furthermore, no significant differences in EE1 among AN subtypes (Fig. 1f) and initial BMI (Fig. 1g) were noted.

Secondly, we examined how the factors correlating with EE1 affected weight gain. Each item that correlated with EE1 was divided into two groups based on initial values, and the results of the comparison of the mean EE1 of each group are shown in Table 2. When divided into two groups, all items correlating with EE1 had a point at which a significant difference in EE1 was noted, with the mean EE1 in the groups with BFM ≤ 3 kg (p = 0.003) (Table 2a), BFP ≤ 8% (p = 0.008) (Table 2b), SLP > 85% (p = 0.011) (Table.2c), and BWR > 0.665 (p = 0.011) (Table 2d) was found to be higher than that of the other groups. <Table 2 insert here>

Table 2 Comparison of the mean excess energy to increase 1kg body weight for each group

body fat mass

initial BFM (kg)	N	EE1 (kcal/kg)	p
≦2.5	24	13565	0.0610
＞2.5	15	11516
≦3.0	27	13800	0.0028
＞3.0	12	10473
≦3.5	32	13264	0.0496
＞3.5	7	10549
≦4.0	33	13200	0.0619
＞4.0	6	10447

EE1; excess energy to increase 1kg body weight, BFM; body fat mass

body fat percentage

initial BFP (%)	N	EE1 (kcal/kg)	p
≦7.0	21	13475	0.1607
＞7.0	18	11962
≦8.0	25	13816	0.0075
＞8.0	14	10921
≦9.0	25	13816	0.0075
＞9.0	14	10921
≦10.0	30	13200	0.1504
＞10.0	9	11366

BFP; body fat percentage

soft lean percentage

initial SLP (%)	N	EE1 (kcal/kg)	p
≦84	7	10798	0.0829
＞84	32	13210
≦85	13	10896	0.0107
＞85	26	13718
≦86	15	11249	0.0216
＞86	24	13732
≦87	17	11499	0.0335
＞87	22	13765
≦88	18	11962	0.1607
＞88	21	13475

SLP; soft lean percentage

body water ratio

initial BWR	N	EE1 (kcal/kg)	p
≦0.655	7	10798	0.0829
＞0.655	32	13210
≦0.660	8	10599	0.0365
＞0.660	31	13339
≦0.665	13	10896	0.0107
＞0.665	26	13716
≦0.670	15	11249	0.0216
＞0.670	24	13732
≦0.675	15	11249	0.0216
＞0.675	24	13732
≦0.680	18	11962	0.1607
＞0.680	21	13475

BWR; body water ratio

No correlations between EE1 and BW, age, total body water (TBW), intracellular water, extracellular water (ECW), and ECW/TBW were observed (data not shown).

This study, which was conducted in a long-term in-patient controlled setting where patients could not purge or engage in hyperactivity, examined the energy requirements and influencing factors during weight recovery in patients with AN. Our results showed that patients with AN required a greater energy intake to gain weight than that required for healthy individuals [7]. Furthermore the amount of energy intake required in patients with AN to gain weight varied considerably, and the body compositions, namely the ratio of FM to SLM, prior to renourishment affected the energy requirements.

Weight recovery is one of the core principles of AN treatment and the first goal of treatment. However, there are conflicting reports on the amount of energy required to gain 1-kg BW for patients with AN, which may explain the inconsistencies in the current guidelines regarding the amount of calories required for weight recovery in these patients.

The current study showed that patients with AN needed 12777 kcal to gain 1 kg during the weight recovery period. According to previously reported studies on overfeeding (16), approximately 10500 kcal of energy was needed to gain 1-kg BW in healthy individuals, indicating that patients with AN may have required more energy to gain BW compared with healthy individuals. Some studies have directly compared the amount of energy required to gain weight in patients with AN with that required for healthy controls. Forbes et al. reported that healthy controls needed more energy than patients with AN (AN, 4730 kcal/kg; control, 7090 kcal/kg). However, the AN group consisted of seven women and one man, while the control group consisted of only men (n = 17). Furthermore, only three individuals from the control group and the AN group were directly compared (17). These factors may have caused the inconsistencies with our results.

Although not a direct comparison of excess energy required for weight gain, resting energy expenditure (REE) was reported to increase in both healthy participants and patients with AN during weight gain. Furthermore, the increase in REE in healthy patients was proportional to the increase in fat-free mass (FFM), while the increase in REE in patients with AN was disproportionately greater than the increase in FFM (18)(19). There are large individual differences in the energy required for weight gain in healthy persons, which may be affected by factors such as hereditary characteristics (20) and non-exercise activity thermogenesis (NEAT) (21)(22). Although the current study was conducted in a prison setting and the behaviors and activities of the participants were strictly monitored, hyperactivity is one of the symptoms of AN. An increase in NEAT may have affected the increase in EE1. Furthermore, diet-induced thermogenesis (DIT) is also one of the factors that affect energy expenditure. DIT is said to account for approximately 10% of energy consumed and varies between individuals (23). Therefore, it may account for individual differences in EE. It has also been reported that in AN, DIT is greater with increased energy intake, which may explain how EE is greater in patients with AN than that in healthy women (11).

Our group has previously reported gut dysbiosis in patients with AN (4). Also, germ-free mice transplanted with feces from patients with AN showed a decrease in BW gain and nutritional efficiency compared with mice transplanted with feces from healthy donors (24). It has been speculated in the livestock industry that intestinal bacteria influence weight gain and loss, as antibiotics in livestock produce weight gain and antibiotics in germ-free animals do not produce this weight gain effect (25). These reports indicate that abnormalities in gut microbiota in patient with AN may also affect the energy cost of weight gain.

Several studies have investigated the amount of energy required to gain weight, with results varying widely among the studies and among participants in the same study (6)(7)(8)(17)(26)(27)(28)(29). Our results showed that the energy cost to gain 1-kg BW was 12777 kcal/kg, higher than that reported in most previous studies, but relatively similarly to the values observed by Yamashita et al. (28). Some differences exist between our study and the study by Yamashita et al. which included patients in the general hospital setting and measured body composition using dual-energy X-ray absorptiometry. Nonetheless, the following similarities should be noted: 1) all participants were Japanese (Asian); 2) the observation period was longer than that in other studies (current study, mean 302 days; Yamashita et al. study, mean > 112 days; Gentile et al. study, mean 90 days); 3) caloric intake of participants was based on the daily requirements of a healthy woman, while caloric intake was greater than that required by healthy women in other studies (Russell et al., 3500–5500 kcal/day and Gentile et al., 1199–2935 kcal/day). The aforementioned factors may explain the inconsistencies between the results of the present study and previously reported studies.

As previously noted, the amount of energy required to gain 1 kg during the weight recovery period of patients with AN varied greatly among participants in the same study. In previous studies with more than 10 patients, the CV ranged from 25.4–95.4% with a smaller number indicating a smaller degree of variability (7)(8)(26)(28). The CV in our study was 26.1%, indicating that the amount of energy required to gain 1 kg varied among participants, excluding outliers, although by a smaller amount than that reported in other studies.

Regarding influencing factors, one study reported that patients with AN restricting-type (AN-R) required more energy for weight gain than patients with AN binge-eating/purging type (AN-BP) (7), while another study reported opposite results (30). Additionally, patients with FM < 4 kg or BMI < 14 kg/m² prior to refeeding required less energy for weight gain compared with those with FM ≥ 4 kg or BMI ≥ 14 kg/m² (28). In our study, we found a relationship between EE1 and factors including FM, FMP, SLP, and BWR, although the subtype of AN and BMI did not appear to be associated with EE1. EE1 was significantly higher in patients with initial FM ≤ 3.0 kg, FP ≤ 8.0%, SLP > 85%, and BWR > 0.665 values, suggesting that the amount of energy required to gain weight may depend on the ratio of fat to muscle (i.e., how undernourished or hyperactive the patient is), rather than their physique.

Considering that the participants in the present study included old and undernourished individuals, the effects of sarcopenia should also be considered, particularly in terms of re-nutrition and rehabilitation. Only three cases in our study population (all in their 40s) had an SMI < 5.7 kg/m² that met the diagnostic criteria (Asian Working Group for Sarcopenia 2019) for sarcopenia. However, by approximately the end of the initial month, these cases no longer met the diagnostic criteria; therefore, the overall impact of sarcopenia was not considered.

The inconsistencies between our results and those of previous studies may be explained by following: 1) the number of participants in our study was larger than that in previous studies, 2) our participants were older than those in previous studies, and 3) setting for our study was a medical prison, with strict observation conditions. In a previous study that did not investigate the energy required to gain weight, anxiety, abdominal pain, activity level, and smoking were reported as factors that increase REE in patients with AN [8]. An increase in the actual REE could increase the resultant energy value for weight gain, as the REE in our study was determined based on Scalfi’s formulation. We did not investigate anxiety or abdominal pain, and our participants did not smoke as smoking is prohibited in medical prisons in Japan. However, activity levels and NEAT may have affected our results. Patients with hyperactivity may experience increased NEAT and require more energy, even if their activity levels are restricted. To better evaluate the amount of energy required for weight gain, activity meters or metabolic rooms are essential.

The strengths of the current study include that the medical prison setting which allowed us to observe the participants for a longer period of time and under more strictly controlled conditions than those in place in other hospitals in Japan. Considering the typical traits of patients with AN, this may be an important factor in accurately investigating the number of calories consumed. Furthermore, this study included a larger number of participants compared to that in previous studies.

The current study also has several limitations. First, we could not exclude the possibility of a gap between the calculated total energy expenditure (TEE) and actual TEE values, as we did not use an indirect calorimeter or an activity meter. Second, the participants in the current study were older than the average patient with AN; hence, our results may not be applicable to patients in their teens or twenties, which is the average age for patients with AN. Third, since Scalfi's formula is designed for females under the age of 30 years, it may not be suitable for use in patients aged 30 and above. Nonetheless, we decided to use this formula as there is no alternative well-established formula for the calculation of BMR in patients with AN aged 30 and above.

Patients with AN required approximately 12800 kcal of excess energy for a 1-kg BW gain, although individual differences were considerable. Furthermore, severe malnutrition and hyperactivity in patients may lead to a greater energy requirement in order to gain weight. Therefore, a greater energy intake in severe cases of AN, with individual adjustments based on weight gain progress in renourishment periods, is critical.

AN

anorexia nervosa

BIA

multifrequency bioelectrical impedance

BW

body weight

EE

excess energy

EE1

excess energy to increase 1kg BW

BMI

body mass index

AN-BP

binge eating / purging type of anorexia nervosa

CV

coefficient of variation

BFM

body fat mass

BFP

body fat percentage

SLM

soft lean mass

SLP

soft lean percentage

BWR

body water ratio

TBW

total body water

ECW

extracellular water

REE

resting energy expenditure

FFM

free fat mass

NEAT

non-Exercise Activity Thermogenesis

AN-R

restricting-type of anorexia nervosa

FM

fat mass

Ethics approval and Consent to Participate

This study was approved by the Kitakyushu Medical Prison Ethics Review Committee and the Kyushu University Research Ethics Committee [22013-00]. The need for informed consent was waived by both review committees due to the retrospective nature of the study. All research involving human data was carried out in accordance with the Declaration of Helsinki.

Because the study was as retrospective study using medical charts of patients who were treated in the Kitakyushu Medical Prison, we were unable to contact the individuals after their release from prison to obtain direct consent to participate.

Consent for publication

Not applicable

Data Availability

The datasets generated and/or analysed during the current study are not publicly available due to privacy or ethical restrictions but are available from the corresponding author on reasonable request.

Competing interests

The authors declare that they have no competing interests.

Funding

This work was partly supported by JSPS KAKENHI Grant Number 23K02918.

Authors’ contributions

CAS designed, collected and analyzed the data. ST analyzed the data. TM collected the data. ST, JK, TS, KT, MY, TH, and NS provided advice on the results and the drafting of the manuscript.

Acknowledgement

This work was partly supported by JSPS KAKENHI Grant Number 23K02918.

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Factors related to required excess energy for weight gain in patients with anorexia nervosa under strict behavioral control: a study in a Japanese medical prison

Status:

Journal Publication

Version 1

Abstract

Background

Methods

Results

Conclusions

Figures

Background

Methods

Participants

Treatment

Anthropometry

Calculation of the excess energy required to gain weight

Study of the factors for weight gain

Statistical analysis

Results

Clinical characteristics

Excess energy required to gain weight

Factors for weight gain

Discussion

Conclusions

Abbreviations

Declarations

References

Status:

Journal Publication

Version 1