How much should I feed my 7 year old lab

Question
He is very active and seems to burn off everything he eats just wagging his tail.

Answer
How much do you feed him now and how much does he weigh?  If he is a good weight now, that's the amount you should feed.  All dogs are different.  Some labs lose weight on 4 cups a day, some gain on 2 cups a day.  It would also help to know what you are currently feeding as well.