I myself have only gone about 100 hours without any sustenance besides liquids and it was one of the most challenging events of my life. I was handed a bottle of Gatorade at the end of the sere course and could only take sips of it. It tasted thicker than a chicken broth and seemed to fill me up entirely. So much so I sicked up and got stomach cramps for awhile. It took a couple of days of very bland food in small portions before I didnt feel somewhat ill after eating.
Everyone is very different
I go 60 hours quite frequently and don't even really notice, have done 10 day fasts and worked at the same time, admittedly when I was younger.