Protective Misperception? Prospective Study of Weight Self-Perception and Blood Pressure in Adolescents With Overweight and Obesity.

PURPOSE: Underestimating one's weight is often seen as a barrier to weight loss. However, recent research has shown that weight underperception may be beneficial, with lower future weight gain and fewer depressive symptoms. Here, we examine the relationship between adolescent weight underperception and future blood pressure.

METHODS: Using data from the National Longitudinal Study of Adolescent to Adult Health, we obtained a nationally representative sample of 2,463 adolescents with overweight and obesity (students in grades 8-12 in 1996). We used multivariable linear regression to prospectively examine the relationship between weight self-perception in adolescence and blood pressure in adulthood (year 2008; follow-up rate 80.3%), controlling for age, gender, race/ethnicity, smoking, alcohol consumption, education level, household income, and body mass index. Additional analyses were stratified by gender and race/ethnicity.

RESULTS: Youth with overweight/obesity who underperceived their weight had lower blood pressure in adulthood than those who perceived themselves to be overweight. The decrease in systolic blood pressure was -2.5 mm Hg (95% confidence interval: -4.3, -0.7; p = .006). Although the interaction by gender was statistically insignificant (p = .289), important differences appeared upon stratification by gender. Young men showed no significant difference in adult blood pressure related to weight self-perception. Conversely, in young women, weight underperception was associated with an average decrease in systolic blood pressure of -4.3 mm Hg (95% confidence interval: -7.0, -1.7; p = .002).

CONCLUSIONS: Contrary to conventional wisdom, weight underperception is associated with improved health markers in young women. The observed differences in blood pressure are clinically relevant in magnitude, and interventions to correct weight underperception should be re-examined for unintended consequences.