How long are you going away for? If its just a week, do a good water change before youu go and then leave it all and enjoy your holiday. Your fish will be absolutely fine without feeding for a week.
Alternitively if you have someone to look after the fish for you, measure out the feeding amounts you want to feed, wrap them in tin foil and hide the rest of your food. That means whoever is feeding for you will have pre-packed food to give on whatever days you specify and cannot overfeed. Hide the rest in case they think the fish want a bit more!!