Letter: Relationships among Body Mass Index, Body Image, and Depression in Korean Adults: Korea National Health and Nutrition Examination Survey 2014 and 2016 (J Obes Metab Syndr 2019;28:61–8)

Depression is a prevalent psychiatric disease in Korea. Studies of depressive outcomes account for much of the growing literature on the relation between obesity and psychological morbidity.1 Hong and Hong2 investigated the association between body mass index (BMI) and depression, in addition to the relationships between body image perception, weight control behaviors and depression. They found that the risk of depression was higher in the underweight group than in the obese group. In multivariate analyses, the risk of depression was also high in the underweight group and the participants who perceived themselves as extremely lean or extremely obese. They found that weight control behaviors, such as fasting, skipping meals, and reducing food consumption were associated with increased prevalence of depression. The strength of this study is that it was conducted using data from a large, nationwide Korean-representative survey.

In the same context, Kim et al.3 investigated the relationships between body weight perception, disordered weight control behaviors, and depressive symptoms also using data from the Korea National Health and Nutrition Examination Survey. They reported that among women with obesity, those who underperceived their weight status showed less depressive symptoms compared to those who accurately perceived their weight status. In addition, among women with normal weight, those who overperceived their weight status reported more depressive symptoms compared to those who accurately perceived their weight status. However, this association was not seen in men. A recent study conducted in 72 countries found that Koreans have the highest preference for thin individuals over individuals with overweight or obesity compared to the participants from all other countries.4 The rapid social changes characterized by industrialization, urbanization, and Westernization over the past half-century in South Korea have flipped the traditional norms and values regarding body image.5 As a result, the thin-ideal is prevalent in South Korea, and having a slim body is viewed as an essential component for a successful marriage and career.5 Hong and Hong2 reported high proportions of women and young adults as well as a high prevalence rate of cancer in the underweight group. The underweight group was found to have a low alcohol consumption rate, which might be due to stop drinking with the consequences of harmful health problems, and also had the highest level of stress awareness. The authors2 noticed that these results appear to reflect the fact that younger participants, especially women, are more easily affected by the social ideology preference for a thin, slim figure.

However, if the data were divided only by sex, the lack of research analysis by sex differences in relation to obesity and depression should be considered. For women, menopause is a significant life event, which in itself affects mental health, and is associated with depression.3 In Mexican population studies,6 obesity was associated with depression in women, whereas no association was found for men. Sex differences in the association between obesity and depression may be explained by cultural, ethnic, and social factors.7 Women are more frequently exposed to media, such as magazines and TV programs depicting “ideal bodies.”7 However, there was a negative association between BMI and depression in middle aged and elderly Chinese men, but not in women.8 They noticed that early childhood starvation plays an important mediating role in this relationship.8 This is an important explanation for the impact of obesity on reducing depressive symptoms in the interaction between early childhood experiences of starvation and the Chinese culture of “body fat represents wealth” which affects individuals’ dietary habit.9 Jung et al.10 showed that underweight increases the risk of developing depression in both longitudinal and cross-sectional studies. In addition, cohort studies showed that overweight reduces the risk of depression in men and increases the risk of depression in women. The association between overweight and depression differed by sex. It seems that the current ideal of thinness affects women more than their male counterparts and causes more psychological distress in women, which can, in turn, lead to depression.10

Obesity and underweight, disordered perception of body weight, and body image dissatisfaction cause mental distress and depression. In clinical practice, medical care providers should pay attention to the mental health of people who are underweight. Likewise, women who are overweight and obese populations should also be monitored for possible depression. Society needs to have attention and support on attempts to achieve healthy body weight.