how much to feed a lab

Question
My yellow lab recently does not want to eat. She is 6 1/2years old; I wonder if I should cut her down to one feeding a day. She has always been a typical lab eating whenever and with excitement. Now she will only eat if I bribe her with some peanut butter mixed in...etc. She will leave her food sitting all day otherwise. At first it seemed submissive, but now I am worried.

Answer
A 6 1/2 year old dog is ALMOST a senior.  I would take her to the vet and make sure she is 100% healthy.  You will want to have the vet do a full blood panel to make sure nothing is wrong.  A dog, even a senior, should not be losing its appetite.  

But you did not say how much you are feeding.  Typically a lab will do fine on 1 or 1 1/2 cups of good commercial kibble 2 times a day.  I would NOT drop the meals to only 1 a day.