When I do HIIT sessions I do it later in the day on an empty stomach. Since I do my workouts after work and thats always about 1 - 2 hours after I eat a snack. I have never had any problems with it, always felt good during & after a good session. Basically IMHO there never is a "bad" time to exercise. There are optimal times but never really a "bad" time. Just do whatever works best for you and whenever you have time for a workout take advantage of that time. Its better to do it at a non-optimal time than to not exercise at all. At least thats what I think
