Exploratory Study of Soft Drink Intake, Diet, and Body Size Among Employees at a Japanese University Aged 20-39

Background: Studies outside Japan have linked sugar-sweetened beverage (SSB) intake with weight gain; however, evidence in Japanese adults is scarce, and no study has examined beverage-derived energy in relation to anthropometric indices and handgrip strength. Methods: The participants were employees of Fujita Health University aged 20-39 years (n = 76; male n = 35, average age: 29.97 ± 4.67 years; female n = 41, average age: 27.29 ± 4.53 years). Energy from beverage intake was assessed via the Brief Beverage Intake Questionnaire-15, and energy from alcoholic drinks, milk, SSBs, and total beverages was calculated. The associations of energy from different beverages with nutrient intake, BMI, skeletal muscle mass index (SMI), and handgrip strength were analyzed via ordinary least squares (OLS) regression; quantile regression (QR) and the generalized additive model (GAM) were used for sensitivity analyses. Results: Increased SSB intake was associated with increased BMI (standardized β = 0.35, 95% CI 0.12-0.58, p(OLS) < 0.001; p(QR) = 0.23; p(GAM) < 0.001) and was nonlinearly associated with increased SMI (standardized β = 0.21, 95% CI 0.043-0.37, p(OLS) = 0.02; p(QR) = 0.11; p(GAM) = 0.02), even after adjustment for total energy intake. Modest milk intake was linked to higher protein intake and a higher SMI without a higher BMI (standardized β = 0.18, 95% CI 0.020-0.35, p(OLS) = 0.03; p(QR) = 0.39; p(GAM) = 0.03). Conclusions: A positive association was found between SSB intake and both BMI and SMI and between MILK intake and SMI. Clarification in larger, diverse Japanese populations will be necessary.