Background: Reports on pulmonary function in overweight and obesity are conflicting. Objective: The objective of the study was to evaluate the effect of increasing weight on dynamic pulmonary parameters. Methods: A cross-sectional study involving healthy young adult male Bengali subjects was carried out in a tertiary care center in eastern India. The subjects were stratified into underweight, normal, and overweight based on their body mass index (BMI). Forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), FEV1/FVC ratio, forced expiratory flow between 25 and 75% of vital capacity (FEF 25-75% ), and peak expiratory flow rate (PEFR) were measured. Results: Out of 153 male subjects, 27 were underweight, 96 were normal, and 30 were overweight. All the subjects were between 18 and 23 years. Median height, weight, and BMI were 170 cm, 60.1 kg, and 21.46 kg/m 2 , respectively. Median FVC, FEV1, FEV1/FVC, and PEFR were 3.806 L, 3.2271 L, 85.22%, and 7.024 L/s, respectively. None of the respiratory parameters differed significantly between normal and overweight although lower FVC and higher FEV1/FVC was noted in underweight. Median FVC, FEV1, and PEFR were lowest in underweight and highest in overweight group. Weight had significant positive correlation with FVC, FEV1, and PEFR while BMI with FVC. Both weight and BMI negatively correlated with FEV1/FVC. Conclusion: FVC, FEV1, and PEFR tend to increase while FEV1/FVC tends to decrease with increase in weight in adult healthy non-obese male.