GDP growth slows down despite eating more: Although consumption is greater at this time of year, it seems that a one hour increase in fasting actually leads to a 0.7% decrease in yearly economic growth, a 2015 study by public policy professors Filipe Campante and David Yanagizawa at the Harvard Kennedy School on the economic impact of Ramadan (paywall) finds. This negative spillover effect was found to affect all measures, including GDP per worker, per capita, and total GDP. All things equal, those measures were found to be negatively correlated with fasting hours. The researchers exploited the fact that countries further away from the equator experience a larger variation in fasting hours, thereby allowing them to base findings on fasting hours alone.

A separate, 2011 study revealed that since Muslim economies lose an average of 40 working hours during Ramadan, GDP, in turn, decelerates 7.7% during the month. Both studies suggest that output losses from there being less business more than offset gains from increased food consumption, the latter also being known as the notorious “Ramadan effect.”