The fact your dog has already lost 2lbs in 6-8 months means you are doing something right and heading in the right direction.

You don't want the weight to come off too fast. And I'm lousy (I mean really lousy) at math, but if I figured it right 2 lbs off of a 27 lb dog is about 8% loss of body weight! That's a fair amount assuming my math isn't way off. You have to remember that while 2 lbs doesn't seem like much to a human size, it's alot compared to a small animal size.

Keep up with what you have been doing, limit the treats and other people sneaking him food. I agree with what the other posters have said with splitting the feedings to twice a day and adding a good 10 minute walk a day. You'll get there eventually, you're already on a good start.

Good luck.