The image in the mirror or the number on the scale, which counts? When it comes to depression, it’s a weighted issue.

August 26, 2022

From mutations of coronavirus to massive shifts in technology and geopolitics, the world is changing rapidly. So, too, is the epidemiological relationship between depression and obesity.

Arsh Kaur Mallhi, a fourth-year doctoral student in the Jiann-Ping Hsu College of Public Health (JPHCOPH) at Georgia Southern University, recently published on this topic in the Journal of Psychiatric Research. Co-authors include Georgia Southern epidemiology professors Jian Zhang, M.D., and Kelly Sullivan, Ph.D.

The study updates research conducted by Zhang 10 years ago, in which Georgia Southern students reported that what women saw in the mirror, not the number on the scale, influenced their mood. A woman who had a healthy weight but was wrongly self-perceived as being overweight was most likely to feel depressed. 

Further, the concern with self-body image, although mostly misperceived, was highly prevalent among women, causing major distress or problems in social life, work, school or other areas of functioning. 

Zhang believed it was time to reevaluate how the intertwined relationship between leading chronic conditions had evolved, and tasked Mallhi with research on the psychiatric impact of obesity. 

New analyses conducted by the team found that among white women, actual body weight is becoming a stronger predictor of depression while self-perceived obesity is becoming less influential.

This switching pattern shows that white women have gradually paid more attention to the number on the scale. Excessive body weight, reliably detected by a scale, may contribute to depression, which can be a strong predictor of various chronic conditions, such as diabetes, cardiovascular diseases and even cancers. 

“The switch makes the efforts in promoting bodyweight-related physical and mental health more harmonious,” said Mallhi. “Unlike what was reported previously, excessive body weight is associated with both physical and mental health. The increasing popularity of the body-positivity movement might be the driver behind the diminishing association between perceived body image and depression in white women.”

Mallhi’s study found no association between body weight and depression among Black and Hispanic women, neither self-perceived nor measured by the scale.

“We should look at this from a dichotomous perspective,” said Zhang. “No relationship suggests low social pressure to maintain body weight and a low risk of psychological and emotional strains. However, low pressure to maintain a healthy body weight may also be translated into no motivation or no action to achieve a healthy weight, presenting an immense challenge to obesity-prevention efforts.” 

Sullivan noted that they aren’t surprised that the relationship between body weight and depression has evolved in sex-race-specific trajectories as society becomes more diversified culturally.

“One-size-for-all public health intervention rarely exists,” she said. “A unified intervention approach may be counterproductive between segments of the population. The public health approach must be consistently fine-tuned to adapt to our rapidly evolving world. Culturally competent interventions should be explored.”  

The Georgia Southern team examined data from 27,387 men and women who participated in the Centers for Disease Control and Prevention’s annual National Health and Nutrition Examination Survey from 2005 to 2018. Depression was ascertained using the Patient Health Questionnaire, a commonly used tool to assist primary care clinicians in screening for depression. Participants were also asked whether they considered themselves to be underweight, overweight or about the right weight before nurses measured their body weight and height to calculate their body mass index.

The COVID-19 pandemic exacerbated both weight gains and anxiety, making addressing obesity and depression more urgent, said JPHCOPH Dean Stuart Tedders, Ph.D.

“COVID presents opportunities to address health emergencies with a newfound urgency,” Tedders said. “The JPHCOPH strives to provide opportunities to maximize each student’s potential, and more and more of our students are publishing their work in top journals to advance public health research and inform public health policy. I am very proud of what our students are achieving. Arsh’s study is just one example of the many ways in which our students are impacting the public’s health through their education and beyond.”