Fasting does not necessarily make people sleep less. However, there are several factors that may contribute to a change in sleep patterns during fasting.
Firstly, during fasting, the body is undergoing a metabolic shift from using glucose as its primary source of energy to using stored fat. This shift in energy source can cause some individuals to feel more awake and alert.
Secondly, fasting can also lead to an increase in cortisol levels, which is a hormone that regulates energy levels and stress response. High cortisol levels can make it more difficult to fall asleep and stay asleep.