i think it depends on your goals. if i'm dieting, i will take some gh first thing in the morning along with my clen and t3 and then do fasted cardio. if this isnt your goal, the way i understand it, you can take it regardless of food. you're introducing exogenous into your body. your body doesnt have to convert anything or change anything to get the gh. you just inject it in and it's in.
the problem with gh and eating to grow is that gh lowers insulin sensitivity. enough gh and you may have a harder time using the food you eat. thats why many guys use insulin with gh. if you are taking 8 or more IUs, i would consider researching insulin and seeing if that is an option.