Childhood and adolescent obesity is a public health concern worldwide. However, little attention has been paid on status of overweight and body composition of Indian Bengali urban middle and high SES population. The objective was to determine the prevalence of overweight and body composition status by age and sex in children, adolescents and young adults. This cross-sectional study was carried out among 4194 unmarried school and college students (1999 males and 2195 females) aged 7–21 years belonging to the Bengali Hindu Population in Kolkata, India. The survey period was from 1999 to 2011. Anthropometry of participants were measured. Age and sex specific ≥85 percentile of body mass index (BMI) for children (<18 years of age) and BMI ≥23 kg/m2 (≥18 years of age) for adults were used to define overweight. Fat percent, upper arm fat area (UAFA) and upper arm muscle area (UAMA) were estimated. Simple linear regression was performed to check trend of changes with age. The overall prevalence of overweight was 14.8% in both sexes. Mean fat percent was higher in females than males (23.5% vs 13.5% respectively; p<0.001) and it increased by 0.18% (0.02) in males and 0.56% (0.02) in females per year (both p<0.001). UAMA gradually increased with age in both sexes and increasing rate per year was by 2.07 (0.04) cm2 in males and 1.19 (0.04) cm2 in females (both p<0.001). However, UAFA increased by 0.41 (0.03) cm2 and 0.90 (0.03) cm2 every year in males and females respectively (both p<0.001). Sum of biceps, triceps, subscapular and suprailliac skinfolds increased by 1.66 (0.06) mm and 0.5 (0.07) mm per year in females and males respectively (both p<0.001). Overall prevalence of overweight was the same in both sexes but adipose tissue was higher and muscularly was lower in females than males.