Association between body fat percentage and non-dietary lifestyle imbalance in adults

Abstract

Objective: With the implementation of the National Fitness Strategy in China, enhancing physical fitness and improving health have become major public health goals. This study utilized data from the National Health and Nutrition Examination Survey (NHANES) to investigate the potential association between body fat percentage and non-dietary balance in daily life among adults aged ≥18 years. Methods: Data from NHANES 2013–2018 were pooled. Demographic characteristics (sex, age, race/ethnicity, education level, household income), body composition (body fat percentage), and questionnaire information (dietary patterns) were extracted. Statistical analyses were performed using SPSS 27.0, R 4.4.1, and Origin 2021, including univariate and multivariate logistic regression, restricted cubic spline (RCS) modeling, and Bootstrap-based mediation analysis. Results: A total of 7,387 participants were included (3,576 males and 3,811 females), with a mean age of 39.48±11.39 years and a median body fat percentage of 33.1%. Among them, 1,840 (24.9%) were classified as balanced-diet and 5,547 (75.1%) as unbalanced-diet. Individuals in the unbalanced-diet group exhibited higher body fat percentages. Multivariate logistic regression indicated significant associations of race/ethnicity, education, household income, and body fat percentage with non-dietary imbalance (P < 0.05). RCS analysis revealed a nonlinear relationship between body fat percentage and dietary imbalance (P < 0.01). Mediation analysis demonstrated a significant total effect [OR = -0.026, 95% CI (-0.041 to -0.011), P=0.001], with a direct effect of body fat percentage on non-dietary imbalance [OR = -0.012, 95% CI (-0.027 to -0.002), P < 0.05]. Household income [OR = -0.007, 95% CI (-0.022 to -0.003), P < 0.05] and race/ethnicity [OR = -0.007, 95% CI (-0.013 to -0.007), P < 0.05] exerted significant indirect effects. Conclusion: Higher body fat percentage is directly associated with non-dietary imbalance among adults, with household income and race/ethnicity playing mediating roles. This relationship appears nonlinear. These findings highlight the importance of maintaining a healthy dietary structure and reducing body fat percentage to lower lifestyle-related health risks, although further empirical studies are warranted.