For me it’s the thoughts that are the bane when it comes to fasting. The hunger is interpreted as a pleasant abnominal massage. The thoughts create the craving and the self-imposed frustrations of those desires throughout the day that are the only burden on a fast, at least for me. If I effectively engaged myself with a task all day I wouldn’t even know I’m fasting and could go forever
Eating food is like a drug and a form of escapism. It numbs the mind and body to a degree depending on what you eat and how much you eat. It keeps us from having to face our inner demons (Unprocessed emotions and traumas gathered from a lifetime). Once you stop eating and fast you are gradually forced to face these demons, then deal with them and let them go.