Diet quality, physical activity and body composition among university students (18–25 years) in urban Chengalpattu, Tamil Nadu, India: a pilot cross-sectional study

Young adulthood is a critical stage for shaping lifelong dietary and lifestyle behaviors. Indian youth are increasingly experiencing declining diet quality, physical activity, and rising overweight and obesity, driven by rapid nutrition transition. However, evidence from smaller urban and peri-urban settings remains limited. This pilot study assessed diet quality, nutrient adequacy, body composition, and physical activity among university students in urban Chengalpattu, Tamil Nadu, India. A cross-sectional study was conducted among 100 students aged 18–25 years. Diet quality was measured along with nutrient adequacy. Body mass index (BMI) and body fat percentage were assessed, and physical activity levels were estimated. Statistical analysis was performed using R Studio. Over half of participants were overweight or obese according to BMI classification, and body fat analysis revealed an even higher prevalence of adiposity, suggesting cases of normal-weight obesity. Diet quality was poor, with high consumption of grain-based foods (95%) and white roots/tubers (44%), but low intake of dark green leafy vegetables (41%), vitamin A–rich vegetables (14%), and fruits (≤ 9%). Nutrient adequacy analysis showed significant deficiencies, with 66% substantially inadequate in calcium, 42% in iron, 100% in riboflavin and 80% in Vitamin B6. In multiple linear regression analysis, total energy intake was significantly associated with higher body fat percentage (β = 0.306, p = 0.003), explaining 16.2% of the variance. For lean body mass, age (β = 0.272, p= 0.001) and gender (β = −0.674, p < 0.001) were significant predictors, with the model explaining 52.3% of the variance. Findings reveal a burden of increased adiposity and micronutrient inadequacy among university students, highlighting the urgent need for nutrition education, healthier food environments, and physical activity promotion in university settings.