It is hypothesized that the syndrome has a genetic basis resulting from an enhanced ability to store fat. The reasoning is that a population stressed by famine would tend to develop this ability. Such a population, exposed to an abundance of rich food would then be at risk to conditions which are associated with obesity.
Evidence found through the study of mitochondrial DNA suggests that there are several factors at play. Subjects of maternal decent from indigeounous populations have several genetic factors that provide more efficient conversion of some classes of carbohydrates into ATP. There is also indication that cellular responses to injury, muscular efficiency, and other metabolic differences may set the stage for other factors to cause the symptoms of the syndrome.
Increased rates of depression are known to produce higher rates of obesity through decreased physical activity. Coupled with a more efficient metabolism this could be a major cause of NWS symptoms within population groups of native decent. As with all studies of the genetic underpinnings of anthropologically diverse groups, the individual circumstances may differ from case to case.