How long after a meal should you wait to workout?
I would advise you to plan a pre-workout meal accordingly. You can eat right before a workout, during a workout, and right after a workout if you planned the meal/food properly. The most recent information on eating is that you should eat smaller meals throughout the day and the caloric intake is determined by what you plan to accomplish with your meals and your workouts. If you are still eating large meals, then yes you will want to wait a little while before strenuous exercise.
But I and all of my serious clients work with a dietician who is very good with fueling for athletic activity levels. I give the generic advice that my dietician recommends for me to give to those clients who don’t think they want to go to a dietician. But eventually, if they get serious, they go. It is not like it costs anymore than coming to workout with me (sometimes it is a lot less actually). If you aren’t willing to do your own educational ground work, you need to go to a dietician.