A comparison of body perceptions in relation to measured body composition in young Japanese males and females

Desire for thinness among young Japanese women from the perspective of objective and subjective ideal body shape

I examined the actual situation of the desire to be thin among young Japanese women from the perspective of ideal body shape and actual measured body shape. In total, 90 young Japanese women were evaluated using a questionnaire (perceived body shape and desired body composition change) and assessments of sarcopenia (muscle strength, physical ability, and muscle mass). Participants were classified into the underweight (body mass index [BMI] < 18.5 kg/m2, 74%), normal-weight (18.5 ≤ BMI < 25 kg/m2, 20%), or obese (25 ≤ BMI < 30 kg/m2, 6%) groups. The normal-weight group needed to gain an average of 2.2 kg to reach the objective ideal weight, but participants desired to lose an average of 4.5 kg. The underweight group needed to gain an average of 10.3 kg to reach the objective ideal weight, but participants desired to maintain their current body weight. Data on muscle mass for the diagnosis of sarcopenia showed low values for the underweight group. Most participants were classified into the normal-weight and underweight groups, but these groups showed a high percentage of women with a desire to be thin. The body shape of young adult women should be carefully considered not only as a health issue of thinness during the fertile period but also as a countermeasure to sarcopenia (low skeletal muscle mass) during the aging process.

Relationship of masked obesity to self-reported lifestyle habits, ideal body image, and anthropometric measures in Japanese university students: A cross-sectional study

INTRODUCTION

Masked obesity (MO) is defined as a normal body mass index (BMI) with a high body fat percentage (%BF), and is associated with the onset of lifestyle-related diseases. However, little is known about the current status of MO. Therefore, we investigated the relationship of MO to physical characteristics and lifestyle habits among Japanese university students.

METHODS

Between 2011 and 2019, we conducted a survey of 10,168 males and 4,954 females with BMI within the normal range (18.5 ≤ BMI < 25 kg/m2). MO was defined as %BF ≥ 20% in males and %BF ≥ 30% in females. Students completed a questionnaire containing items about lifestyle habits. Systolic and diastolic blood pressures were measured, and hypertension was defined as systolic above 140 mmHg and/or diastolic blood pressure above 90 mmHg. A multivariate logistic regression analysis was performed to evaluate the relationships as follows: the relationship of masked obesity to self-reported lifestyle habits, ideal body image, and anthropometric measures; the relationship between hypertension and body indices.

RESULTS

The proportion of students with MO in 2019 was 13.4% in males and 25.8% in females, and the proportion of females increased over time. MO was associated with desire for weight loss (odds ratio, 95% confidence interval: 1.76, 1.53-2.02), intake of five macronutrients (0.79, 0.67-0.93), rice and wheat intakes (1.22, 1.01-1.47), sleep duration of < 7hr (0.85, 0.74-0.98), and exercise habit (0.71, 0.63-0.81) in males; and with balanced diet intake (0.79, 0.64-0.99) and exercise habit (0.65, 0.51-0.82) in females. There was a significant association of MO with hypertension in males (1.29, 1.09-1.53).

CONCLUSION

The percentage of female students with MO increased during the study period, and in males, MO may be a risk factor for hypertension. These results suggest that intervention for MO is needed in Japanese university students.

Association of body mass index and its classifications with gray matter volume in individuals with a wide range of body mass index group: A whole-brain magnetic resonance imaging study

Aim

To examine the association of body mass index (BMI) [kg/m²] and its classifications (underweight [BMI < 18.5], normal [18.5 ≤ BMI < 25], overweight [25 ≤ BMI < 30], and obese [BMI ≥ 30]) with brain structure in individuals with a wide range of BMI group.

Materials and methods

The participants included 382 right-handed individuals (mean age: 46.9 ± 14.3 years, 142 men and 240 women). The intelligence quotient was assessed using the Japanese Adult Reading Test. Voxel-based morphometry (VBM) and diffusion tensor imaging (DTI) were performed to analyze the association of BMI and its classifications with gray and white matter structures, respectively.

Results

According to VBM, BMI was significantly and negatively correlated with the bilateral cerebellum exterior volumes. In group comparisons, the right cerebellum exterior volume was significantly lower in the overweight or obese group than in the underweight or normal group, while the bilateral cuneus and calcarine cortex, left cuneus, and left precuneus volume was significantly lower in the underweight group than in the non-underweight group. Sex-related stratification analyses for VBM revealed that BMI was significantly and negatively correlated with the bilateral cerebellum exterior volumes only in women. In group comparisons, the left cerebellum exterior volume was significantly lower in obese women than in non-obese women. The left thalamus proper and the right cerebellum exterior volumes were significantly lower in overweight or obese group than in underweight or normal group in men and women, respectively. The bilateral cuneus and calcarine cortex, left cuneus and carcarine cortex, and bilateral cuneus volume was significantly lower in underweight men than in non-underweight men. In contrast, there were no notable findings on DTI.

Conclusion

Our results suggest association of continuous BMI, being overweight or obese, and being underweight with decreased gray matter volume in individuals with a wide range of BMI group. Furthermore, sex-related differences are seen in the association of BMI and its classifications with regional gray matter volume reductions. Abnormally high or low BMIs may have a negative influence on regional gray matter volumes.

Preoccupation with Body Weight and Under-Reporting of Energy Intake in Female Japanese Nutrition Students

The present study aimed to examine associations between body image and under-reporting in female Japanese university students enrolled in a nutrition degree program. A total of 100 participants (aged 18-29 years) completed (1) a self-administered questionnaire including the Ben-Tovim Walker Body Attitudes Questionnaire (BAQ), (2) a dietary assessment using a brief-type self-administered diet history questionnaire (BDHQ), (3) a physical activity assessment using Bouchard's Physical Activity Record (BAR) and a tri-axial accelerometer, (4) detailed anthropometry, and (5) body composition assessment. Based on the energy intake to basal metabolic rate ratio (EI:BMR) and using a cut-off point of 1.35, 67% of participants were considered under-reporters (URs). While there was no between-group difference in BMI, URs had significantly (p < 0.05) greater percentage body fat (%BF) and trunk fat (%TF) compared with non-URs. Regression analyses indicated accuracy of body perception and a discrepancy between current and ideal weight were associated with EI:BMR, whereas the salience subscale of the BAQ was associated with reported EI. The study raises concerns regarding the validity of EI reported from young Japanese females as they are known to have a strong preoccupation with thinness, even with an acceptable BMI and health and nutritional knowledge.

Body mass index as a moderator of the association between weight status misperception and disordered eating behaviors

Weight status under-perception is protective against disordered eating behaviors and weight gain; however, it is unclear whether under-perception may confer protection across all weight classes. This work explored body mass index as a moderator of the association between weight status perception accuracy and disordered eating behaviors among adults with overweight or obesity. A total of 572 adults (58.7% female; age M = 39.50, SD = 11.57) with overweight or obesity (body mass index M = 31.50, SD = 6.24) completed a series of online questionnaires assessing uncontrolled, emotional, and restrained eating, eating disorder symptoms, weight status perception, and demographics. Controlling for race/ethnicity, age, and sex, linear and negative binomial regressions were used to test hypotheses. Compared to accurate weight status perception, under-perception was associated with less uncontrolled (p = .003) and restrained eating (p = .002). Under-perception was particularly protective against emotional eating (p = .022) and eating disorder symptoms (p = .017) for individuals of overweight or Class I obesity. In general, weight status under-perception was associated with fewer disordered eating behaviors. The protective effects of under-perception of weight status may be maximized for individuals of overweight or Class I obesity statuses.

LOCATION OF BODY FAT AMONG WOMEN WHO ACCURATELY OR INACCURATELY PERCEIVE THEIR WEIGHT STATUS

This cross-sectional study investigated location of body fat, with specific focus on abdominal fat, among normal weight and overweight women who accurately or inaccurately perceived their weight status. Young, adult women (N = 120; M age = 19.5 yr., SD = 1.2) were asked to classify their weight status using the Self-Classified Weight subscale from the Multidimensional Body-Self Relations Questionnaire. Actual weight status was operationalized via dual-energy x-ray absorptiometry. Overweight women who thought they were normal weight had an average of 19 pounds more fat than normal weight women with 1.5 pounds of excess abdominal fat. Interventions to raise awareness among overweight women unaware of their fat level are warranted. However, these interventions should balance consideration of potential detriments to body image among these women.

Which measures of adiposity are related to Australian adolescent's perception of their weight?

AIM

To determine which measurement of adiposity - standardised body mass index (BMI-z), waist circumference or body fat percentage - is most closely correlated with adolescents' weight perception and whether this differs by gender.

METHODS

Weight and height (used to calculate BMI-z), waist circumference and body fat percentage were measured in 2278 adolescents aged between 12 and 16 and compared with self-reported weight status.

RESULTS

The distribution of subjects across the three weight categories (underweight, healthy weight and overweight) differed significantly between BMI-z, waist circumference and body fat percentage (p < 0.001). BMI-z was most closely aligned with perceived weight status in boys and girls, and waist circumference was also a good correlate of weight perception in boys. Boys were more likely than girls to underestimate their weight when it was defined by BMI-z; however, girls were equally likely to underestimate their weight when it was defined by waist circumference. The majority of adolescents underestimated their weight status when it was defined by BF%.

CONCLUSION

BMI-z is the closest correlate of self-perceived weight status. In the absence of internationally accepted reference values for waist circumference, BMI-z is the most appropriate measure to verify weight perception.

Overestimation and underestimation: adolescents' weight perception in comparison to BMI-based weight status and how it varies across socio-demographic factors

BACKGROUND

Weight perception has been studied with a limited focus on "feeling overweight." This study, using a more inclusive definition of overestimation and underestimation, examines adolescents' weight perception focusing on how accurate it is in relation to body mass index (BMI)-based weight status and how it varies across socio-demographic factors.

METHODS

Data are from the 2007 Minnesota Student Survey, a paper-and-pencil survey completed in the classroom by students in public schools. The final analyses were based on the data from 87,418 high school students who were asked about their height and weight.

RESULTS

Weight perception and the BMI-based weight status (based on self-reported weight and height) were strongly and positively correlated, but substantial discordance was observed with more than a quarter of the students (27.6%) having discordant weight perception. Males, minorities, and those from low-income households were more likely than their respective counterparts to have a discordant weight perception. Overall, underestimation was more prevalent than overestimation. Girls were more likely to overestimate, while boys were more likely to underestimate. Black and Hispanic females and those from low-income households were more likely to underestimate than overestimate their weight, while Asian/Pacific Islander males were more likely to overestimate than underestimate.

CONCLUSIONS

If underestimation is more prevalent among Black or Hispanic females and those from low-income households, the already higher prevalence of obesity among these groups is unlikely to decrease. Overestimation, on the other hand, can be a risk factor for unhealthy weight-control behaviors. Monitoring adolescents' perceived weight in addition to their BMI is critical to understanding the challenge we face with childhood obesity.

Body image and eating disorders amongst Japanese adolescents. A review of the literature

This review describes the prevalence of eating disorders and disordered eating behaviors as well as factors influencing body image disturbance amongst Japanese adolescents and compares the prevalence and trends with those of Westernized countries. Although eating disorders have been previously regarded as peculiar to Western society, they are now a more global issue with reports of non-Western countries including Japan having increasing rates of eating disorders. As the aetiology of eating disorders is related to societal norms, culture and ethnicity, their study requires an understanding of body image disturbance within different cultural contexts. Although considered less prevalent than in the West, Japan has an early history of eating disorder research and trends outlined in this review suggest that, as in Western countries the interest in, and study of eating disorders in Japan has increased during the 1980s. The prevalence of eating disorders in Japan based on available reviews, epidemiological studies and clinical reports ranges from 0.025% to 0.2% for AN and from 1.9% to 2.9% for BN. Studies suggest that the prevalence of eating disorders has increased significantly during the past two decades but the prevalence is still quite low compared to those in Western countries. Strategies for culturally appropriate prevention are discussed.