As early as 1962, Neel hypothesized that T2D represented a ‘thrifty genotype’, which had a selective advantage.  He postulated that in primitive times, individuals who were ‘metabolically thrifty’ and able to store a high proportion of energy as fat when food was plentiful were more likely to survive times of famine.  However, in recent years, most populations have a continuous supply of calorie-dense processed food, as well as a decline in their physical activity.  This likely explains the rise in T2D prevalence worldwide.