Globally, annual hungry seasons or seasonal famines have been a part of agricultural societies. Studies say these hungry seasons are associated with decline in fertility. Further, the body adapts to the lack of food by lowering energy consumption (thriftiness). This is followed by rapid deposit of energy as body fat in times of plenty in order to survive periods of starvation. ‘Thrifty gene hypothesis’ has been suggested to be a mechanism for saving or hoarding calories for times of starvation.

Proponents of this theory use it to explain why certain populations, particularly developing agricultural economies, are genetically predisposed to high levels of obesity and type II diabetes mellitus. Such societies exposed to seasonal famines are especially vulnerable to the influences of Western, urbanised obesogenic environment where they escape frugality.

The thrifty gene concept lacks experimental validation but it helps understand whether evolution is to be blamed for our particular susceptibility to obesity and diabetes mellitus. Discovering whether past famines and food scarcity have created especially vulnerable populations, by studying different ethnic/ racial groups and genomes would certainly help us solve this mystery.

Navratras (nine days of fasting and prayers) could be rooted in such agricultural cycle and symbolic of famine followed by plenty. Navratras is observed twice a year by Hindus, according to the lunar calendar. While there must be an astrological significance, its occurrence with harvest time may not be a coincidence. The period before harvest in agricultural societies was marked with frugality and associated with shortage of food.
According to the agricultural calendar, these times are followed by times of plenty.

... contd.