Obesity among teenagers/adolescents and young adults is associated with significant adverse short and longer-term effects on health. To date, no narrative reviews have evaluated nutrition transition and its contribution to the obesity epidemic among adolescents and young adults in the South Asian (SA) region.Data were retrieved by a four-stage systematic search process. A search of the online Pub- Med/Medline, SciVerse Scopus and Web of Science databases was performed. The age groups were defined as follows; teenage:13-19 years, adolescence:10-18 years and young adult:19-24 years.Among teenagers/adolescents, the prevalence of overweight ranged from 11.0% (Sri Lanka) to 19.0% (India), while obesity ranged from 2.4% (Sri Lanka) to 11.0% (Pakistan). In young adults, prevalence of overweight ranged between 7.9% (Nepal) to 15.0% (Pakistan), while obesity showed a much wider variation (0.005%[Nepal] - 22.8%[India]). Nutritional risk factors associated with overweight/ obesity among SAs of this age group included reduced fruit and vegetable consumption, a total vegetarian diet, consumption of fast food and soft drinks, and skipping breakfast. Other contributing factors identified were: adding extra salt to meals, eating meals outside of the home, frequently visiting restaurants and eating while watching television. Daily milk/yoghurt consumption and a family supper have shown a protective effect against overweight/obesity.Overweight and obesity are common amongst teenagers/adolescents and young adults of the SA region. Several food types and habits were identified as being associated with overweight/ obesity in this population. Identifying common protective and contributory factors is very important for the development of a shared regional preventive strategy.