Prevalence of normal weight obesity among adults in Southeast Asia: Insights from a systematic review and meta-analysis.

Background: Normal Weight Obesity (NWO) describes individuals with a normal body mass index (BMI) but elevated body fat percentage (BF%), placing them at increased risk for cardiometabolic complications. This condition is particularly relevant in Southeast Asian populations, where visceral adiposity occurs at lower BMI thresholds. However, regional pooled prevalence data are limited. Methods: A systematic search was conducted in PubMed, EMBASE, Scopus, Web of Science, and Google Scholar for studies published between January 2010 and May 2025. Eligible studies included observational data on adults (≥18 years) from Southeast Asia reporting NWO prevalence, defined by normal BMI (18.5-24.9 kg/m2) with validated surrogate indices indicative of excess adiposity. Two reviewers independently conducted screening, data extraction, and quality appraisal using the Joanna Briggs Institute (JBI) tool. A random-effects meta-analysis was performed using the Freeman-Tukey double arcsine transformation, with heterogeneity assessed via the I2 statistic. Results: Eight studies involving 9028 participants from five Southeast Asian countries (Philippines, Malaysia, Thailand, Myanmar, Singapore) were included. The pooled prevalence of NWO was 57 % (95 % CI: 37 %-75 %), with study-specific estimates ranging from 22.8 % to 82 %. Heterogeneity was high (I2 = 98.9 %). Most studies used bioelectrical impedance analysis (BIA) for body fat assessment and were rated as moderate to high quality. Conclusion: NWO is common among adults in Southeast Asia, especially in women and young adults. These findings highlight the limitations of BMI as a screening tool and support the integration of body fat assessments into public health screening and clinical protocols for early risk detection.