Between 2-3 is good sometimes it can be tough to wait more than 2 but I would never wait more than 3 and if you calculate it right with six meals a day and time for cardio,lifting, etc.. you shouldn't ever get to hungry. One thing I would do though is have your last meal no more or less then 2 hours before you sleep. As to not have you go to bed hungry and so you don't have a ful meal in your stomach when you go to bed.