Adolescents with Normal Weight Obesity Have Less Dry Lean Mass Compared to Obese Counterparts

TL;DR

Adolescents with normal weight obesity have less lean body mass than obese peers, suggesting potential health risks despite normal BMI.

Contribution

This study reports the prevalence of normal weight obesity in U.S. adolescents and compares body composition and dietary habits across groups.

Findings

13.6% of adolescents had normal weight obesity, with higher prevalence in girls.

Normal weight obesity adolescents had significantly lower dry lean mass compared to obese adolescents.

Normal weight lean adolescents consumed more calories and fiber than both normal weight obesity and obese groups.

Abstract

Normal weight obesity (NWO) is a condition characterized by a normal body mass index (BMI; 18.5–24.9 kg·m−2) yet excess body fat. Those with this condition have an increased risk of cardiometabolic diseases associated with obesity. The prevalence of NWO is not well investigated in adolescents, particularly in the United States. This study examined the prevalence of NWO and dietary behaviors among adolescents aged 14–19 years old (n = 139) who live in a rural area in the United States. Data were collected from December 2019 through February 2020. Body composition was assessed via bioelectrical impedance analysis and diet was assessed using an Automated Self-Administered 24 h food recall questionnaire. Participants were categorized by BMI and body fat percentage as NWO, normal weight lean (NWL), or obese (OB). The sample prevalence of NWO was 13.6%, with girls having a higher prevalence (22.2%) than boys (1.8%). Those with NWO had significantly lower dry lean mass than OB (p = 0.02), but there were no differences between NWL and OB (p = 0.08). There was significantly higher caloric intake (p = 0.02) among NWL compared to OB, and NWL consumed more fiber than both NWO (p = 0.02) and OB (p = 0.03). Overall, this study gives us a better understanding of the prevalence of NWO in the adolescent population and the dietary habits associated with each group. Those with NWO may be at increased risk for negative long-term health outcomes commonly associated with obesity. Additionally, the higher caloric intake among NWL was unexpected and should be investigated further.

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