We are always advised to do exercises at least 2 hours before we go to bed or eating. And it makes perfect sense especially the eating part. Can you imagine going to do exercises after you have just eaten? how will it feel, first and foremost the stomach is full, there is that discomfort when you even try to bend, how about jumping up and down, how uncomfortable will that feel. I guess the reason why we are told to do exercises 2 hours before we eat is for us to be comfortable enough to run and jump without vomiting, or having bouts of breathlessness. You will notice that when you workout like that you get tired quickly and you won't be able to do your workout properly. Calories are broken down after food has been digested and turned into fats and sugars, that's when you do exercises and burn the fat and the calories. before that you won't be doing yourself any justice you will only be tiring yourself and your body. And again after you have eaten, you might start feeling sick or get dizzy whereby your heart rate gets increasingly fast which can be very dangerous. So it's good to be advised on this things before you start on any exercises.