Maybe its because you keep filling an empty bowl. Your dog should eat twice a day. Am and pm at the same time everyday. Keep him regimented and his weight will come off. What's the size of your dog? How much you feed him depends on his body weight/height. Is he active?
My cats meow at me all the time Cause they want food- Sorry - They get fed 2 times a day - Noon and 8 pm - They get a small amount of crunchies Around midnight - No more no less- They are healthy n fit- They just wine sometimes cause they think I will feed them - If you give in - They got you - There not starving - Fed well - Cut back on the dogs rations a little at a time - till you get it on a feeding schedule - And don't give in - Being obese is not healthy for the pet And only hurts them in the long run.