Without food, just shy of 24 hours. Slept around 12 hours after almost pulling an all-nighter, then never got hungry enough to get out of my room until late in the night. Was groggy all day, didn't feel hungry for several hours, then it nagged for another few hours until it gnawed at me and I couldn't do anything without thinking about food. So I ate, surprisingly only took a normal-sized meal to satisfy the hunger.

I've gone without water or food for about 9 hours at a time on several occasions. Mostly just makes me lethargic at the end. But the most memorable time was when I went on a trail with a couple friends for about 4 hours. It was the middle of summer in an arid climate and I realized I forgot to bring water about an hour in. Was very parched and heart racing by the end, but didn't bother me too much. Then chugged about 3x 500 mL bottles as soon as I got back in the car.