Rations and Food

How closely do people keep track of food and drink in Fantasy Hero games?  Do you keep track of how much characters eat, use up rations etc, do they have to go hunting and fishing to survive?  Or do they just get to their destination without trouble and you figure they survived somehow?  Does it only come up in specific circumstances like a desert setting?  Do you keep track of rations eaten per meal or just chalk one up each day?  And what about mounts?