Interactive effects of sleep duration and dietary patterns on obesity moderated by age

Over the past decade, Taiwan has seen rising rates of overweight and obesity across all age groups. In a large cross-sectional analysis involving 27,473 adults from the MJ Health Research Foundation, we examined how sleep duration and dietary patterns, stratified by age, relate to obesity and excess adiposity. Participants completed the MJ Health Questionnaire, blood tests, and anthropometric assessments. Four dietary patterns emerged via factor analysis: vegetables and fruits, processed/ultra-processed foods, protein-based, and dairy-complex carbohydrates. Chi-square and t-tests evaluated baseline differences, and multivariable logistic regression modeled the relationships among sleep, diet, and obesity. Short sleep duration was linked to 21% greater odds of obesity than adequate sleep (OR 1.21; 95% CI, 1.15-1.29). The processed/ultra-processed (OR 1.24; 95% CI, 1.16-1.33) and protein-based patterns (OR 1.52; 95% CI, 1.42-1.64) were associated with higher odds of obesity and excess body fat, while the dairy-complex carbohydrate pattern was protective (OR 0.81; 95% CI, 0.76-0.87). Notably, younger adults with insufficient sleep exhibited increased odds of obesity than older adults. These findings underscore inadequate sleep amplifies odds of obesity across dietary patterns and age modifies these interrelationships, highlighting the need for age‑tailored, integrative lifestyle interventions.