Patients Often Underestimate Body Size, Impacting Obesity Care

The interplay between lifestyle, genetics, and environment is recognized as pivotal in developing obesity. However, an often-overlooked aspect, body size perception the individual’s estimation of their body size emerged as a relevant factor in weight regulation. Distorted body size perception, especially underestimation, is prevalent in patients with obesity, influencing their behavioral responses to weight management. A recent study delves into the long-term changes in body size perception after bariatric surgery, offering insights into its association with weight regain.

A Unique Perspective on Body Size Underestimation

The study, part of the Swedish Obese Subjects (SOS) project—a comprehensive investigation into the effects of bariatric surgery evaluated the self-estimated body size of participants before and after bariatric surgery or conventional obesity care. The study provided a unique perspective on the persistence of body size underestimation and its potential impact on weight management. The SOS study, published in Obesity Facts, recruited 2,504 patients who either underwent bariatric surgery (n=1,370) or received conventional obesity care (n=1,134). Researchers matched both groups based on 18 variables to ensure a robust comparison. Verena Parzer and colleagues examined participants at various intervals over 10 years, with weight, height, and BMI measurements, coupled with self- estimations of body size using Stunkard’s  figure  rating scale.

The Enduring Nature of Body Size Underestimation

Key findings shed light on the enduring nature of body size underestimation. Even after significant weight loss from bariatric surgery, patients continued to underestimate their body size, though slightly more accu-rately when compared with those who gained or regained weight (Figure). At baseline, the average underestimation rates were 12% for patients who received bariatric surgery and 14% for controls. “When stratified by long-term weight development, weight regainers from the surgery group underestimated their body size to a larger degree compared with weight maintainers (12% vs 9%, P<0.001) after 10 years,” wrote Parzer and colleagues. “Likewise, weight gainers in the control group also underestimated their body size to a larger degree (17% vs 13%, P<0.001).” Notably, the study revealed that weight maintainers exhibited more accurate body size perception com-pared with weight regainers.

Important Implications

The persistent underestimation of body size, even post-surgery, highlights the need for nuanced approaches to patient counseling and support. The study emphasizes the im-portance of addressing psychological aspects alongside physical interventions, consider-ing the profound impact on long-term weight management. Understanding the association between body size perception and weight regain provides a valuable tool for tailoring interventions. Iden-tifying patients at risk for distorted body size perception can guide personalized treatment strategies that promote better adherence and improved outcomes. The study’s insights into the allocentric lock hypothesis—a concept that suggests patients retain a fixed, long-term perception of their body size—open avenues for further research into the psychological mechanisms in- fluencing weight management.