There is a rapidly increasing epidemic of type 2 diabetes in India and other Asian countries. The thrifty genotype and the thrifty phenotype are two nonexclusive explanations. People in the Indian subcontinent have faced undernutrition for many generations, and Indian babies are among the smallest in the world. However, the diabetes epidemic is of recent origin, and diabetes is more common among urban than rural Indians despite the higher birth weight of urban babies. This suggests that postnatal factors must also contribute. Thus, a life-course model of evolution of insulin resistance and type 2 diabetes, incorporating fetal, postnatal and adult components, seems most appropriate. For a given BMI, Indians have a higher percentage of body fat and more visceral fat than members of other populations.